Just to clarify, I don't believe any of the following arguments and I'm fairly sure they're all bullshit, but I'd like to bolster my understanding of how to refute them the next time I see them.
These are all paraphrased or "steelmanned" (as opposed to strawmanned) versions of arguments I've encountered elsewhere on the internet.
- Israel does not unilaterally blockade the Gaza strip all by themselves; Egypt also has a border with Gaza and also participates in the blockade, and yet pro-Palestinians never seem to allocate any of the blame to Egypt, they always put it entirely on Israel. This is unfair and possibly antisemitic.
- In 1948, the Zionists allowed Arabs who didn't fight against them to stay in their homes and become citizens of Israel. This population of Arabs became known as the "48-Arabs", and they and their descendants are still citizens of Israel today. The fact that the Zionists accepted these people into their new state proves that the Zionists were not aiming to ethnically cleanse all Arabs and that Israel is not a racist state, or at least not a foundationally racist one. If the Arab Palestinian militants of 1948 had just done what the 48-Arabs had done instead of starting a war, they and their descendants would also be full citizens of Israel today.
- Western pro-Palestinian advocates make a critical error when they assume that Palestinians are primarily concerned with "civil rights". The main thing that motivates Palestinians in the West Bank and Gaza (as opposed to Arab Muslim citizens of Green Line ‘48 Israel) is not their lack of "civil rights" (which are a largely Western notion, after all), it's that they resent Israel's existence as a non-Muslim-dominated society in what they see as "Muslim lands". They do not desire a secular democratic state with equal civil rights for all, they desire a Muslim controlled, sharia law state in which they can dominate Jews as a persecuted minority of second class citizens (dhimmi, infidels) or just drive Jews out entirely at their whim. Maybe in 1948 the Arab population of Palestine would have been satisfied with a secular, democratic state, but unfortunately extremist Islam has become a much more prevalent ideology since then and has changed the political equation.
- During the period of the British Mandate of Palestine (roughly 1910s to 1940s), Jewish immigrants improved the living standards of the region and initiated a lot of new economic activity. As a result, many Arab Muslims from neighboring regions like Egypt, Syria, and Jordan immigrated to the Mandate of Palestine because they were attracted by the new economic opportunities, and today's Palestinians in Gaza & the West Bank are largely descended from these Mandate-era Arab immigrants. Given that their ancestors came to Palestine at about the same time that Zionist Jews did (and in some cases later), their claims of having a superior right to the land of Palestine over Israeli Jews don't make sense. (example of this argument can be found here and here)
- Often pro-Palestinian advocates say that "Western countries should have accepted Jewish refugees in the 20th century instead of pressuring them to go to Palestine." This is true on a surface level, indeed a lot of things would have gone better if powerful Western countries had done that. But alas, they didn't, and that wasn't something that the Jews of the time had control over either way. Therefore the Jews who settled in Palestine at that time can't really be blamed for what they did, they were just looking out for themselves in the absence of any benevolent world power who would take them in.
- Pro-Palestinians misunderstand the Haavara agreement and overstate its importance. The fact that the Haavara agreement occurred does not prove that Zionists supported Nazism, or vice versa. If the Haavara agreement "proves" anything, it is simply that for a few years the Zionists had just enough political leverage with the Nazis & British to help out some fraction of German Jews as their situation in Germany was becoming more precarious, and the Zionists took the opportunity to do this while they could. This does not at all prove that the Zionists "supported the Holocaust/allowed it to happen" or anything like that, and the fact that some pro-Palestinians interpret it that way is really rather disappointing.
Israel is the settler-colonial entity controlling all entry and exit for Gaza and that forced Palestinians into Gaza rather than the other places in Palestine most of their families lived in the first place. Palestinians deserve the right to return to those places, not to be forced out of Palestine entirely. Imagine if Egypt did fully allow transit through the Rafah Crossing: you'd just move the suffering a few miles or would see Palestinians forced into exile by the conditions created by Israel. Imagine if the complaint about South African apartheid was that a neighboring country wasn't sufficiently open to accepting the entire population of black people getting pushed out by whites. Imagine if they weren't pointing the finger directly at the apartheid regime that stole their land and brutalized them.
Zionists run the gamut from being okay with a small minority Palestinian population to wanting them all dead. All of these are ethnic cleansing, as the core premise of the ethnostate, the destruction of Palestinian-ness, remains. In addition, the Palestinians that have Israeli citizenship still live under an apartheid system. In addition, consider that Israel calls Palestinians Arabs and not Palestinians because they want to pretend that they are not indigenous to Palestine, which is purely propaganda and a lie. Unfortunately many people take this up,, including anti-Zionists.
This has a false premise. Palestinians are not a monolith, their religious motivations are far more complex and diverse than that, and they 100% are motivated by their conditions and talk about it all the time, including the right to return. Their homes were stolen at gunpoint. They didn't forget that. Their parents were killed by occupiers. They didn't forget that. The pretense that this is just a religious "conflict" is a lie sold to Westerners so they forget that it's about an ongoing settler-colonial project.
This is a nonsense story, pure propaganda told by and for the Zionist entity. The usual line is that they, "made the desert bloom". In reality, conditions didn't improve so much as they were modified for British gain, where Palestine went through a partial industrialization for these purposes. This was not a particularly positive development for Palestinians at it involved the classic enclosure of lands, disruption of communities, and poverty. Zionist settlers tended to arrive with money and buy up properties as they were sponsored by Zionist orgs and antisemitic governments. In addition, they immediately began creating Jewish-only enclaves, European-coded. This created a system by which this alleged "prosperity" was already serving an apartheid system, one that lead to frequent conflicts and in which the British always stood by the settlers.
While Western governments had antisemitic policies that heavily limited immigration just before and during WWII, they barely did before and after when the vast majority of settler immigration occurred. Zionists are also not simply refugees and most have never been refugees. Instead, they are a settler-colonial movement seeking to create an ethnostate where other people already lived and live. Don't confuse the two. Refugees don't all need or try to create ethnostates. They go where they can, where they see a way to find a decent life. It's not like Palestine is in any way the only place they could go. It was chosen specifically to support Zionism, not refugees. In fact, Zionists were highly antisemitic about the diaspora itself and frequently told newcomers the people who died in the Holocaust deserved it because they hadn't been Zionist. Finally, there was just about every other place in the world to go and none of it requires stealing homes and land and orchards from the people already living there. The Soviets even set aside a huge area, larger than Israel, where the diaspora would be free to have an autonomous region. Zionists preferred to steal Palestinian land and support the ongoing apartheid system there. Keep in mind that most Jewish people don't live in Israel.
Zionists and Nazis were buddies. Zionist is not the same as Jewish, it means committed to the settler-colonial project of Israel. Zionists celebrated and even helped create such antisemitic policies in Europe because they used them as a recruiting tool. "It will create a place to send your Jews away to" was the original selling point made to the British, for example. There were policies like the Haavara Agreement all over Europe as part of the Zionist-antisemite partnership, so these relationships are actually undersold, not exaggerated.