Assuming for the sake of argument that all your positions are 100% correct

Even I don't think all my positions are 100% correct, just like how not all scientific claims are always accurate and have to be backed up by replication studies and there has to be experiments and theoretical models and everything, and even then those models are mere approximations of reality. We're all mortal human beings with incomplete knowledge based on propaganda, whether one calls it propaganda or not, and to be even approximately correct on a majority of issues is about as good as one can truly hope for. My problem is when people are unaware of these things and believe that their very clever brains with perfect information (supplied via Washington Post articles or some thinktank or whatever) have Solved The Issue™ and everybody who argues against it must be in bad faith or an evil person or just simply not understand that what they're saying is wrong and bad.

this'd be like saying most of the major high schools and universities are teaching flat earth theory, and it's commonly accepted as true. An argumentum ad populum is of course not logically sound, but to a layperson is compelling. Especially when they grew up surrounded by those that believe in the flat earth. Not only that, but that a flat earth is the morally superior position.

Yeah, I agree, this is a very good point, and it's why it feels like you're so routinely punching a self-reinforcing steel wall when you try and engage with liberals and conservatives (and even sometimes other baby leftists) on some issues. I feel like I had to undergo a sort of ego death - maybe not that drastic - when I transitioned from social democrat to democratic socialist to socialist to Marxist, where I had to let go of my previous programming to do with politics. Of course, we aren't going into dipshit QAnon territory here - scientific facts are facts, and if a scientific study adequately performed (so like, not a climate study backed by ex-fossil fuel industry workers) disproves a part of my worldview then I must let it go; we aren't cranks. Many of us would even say that we take the most scientific approach to politics, hence the half-serious, half-ironic use of "The immortal science of Marxism-Leninism" sometimes.

But so much of politics is up to interpretation, and facts are so often either omitted or overly emphasized to make a point (libs typically call the discussion of these facts "whataboutisms"), and communists can take entirely different framings of issues or reality itself, which makes it extra difficult to communicate effectively with liberals. The political compass is a good example, as most of us simply believe it's a bunch of nonsense that doesn't hold up to serious scrutiny, politicians are almost arbitrarily placed throughout it, left and right, let alone authoritarianism and libertarianism have basically entirely different definitions to a liberal and a communist, and so we laugh at people who make it their identity and have their position in their profile picture. To that person (let's say a 21 year old frequent Reddit user whose only post-school political education has come from memes on social media and the occasional article that comes up on their phone or home page) saying "This is a bunch of bullshit!" might just come across as "We're all in the top/bottom left corner and so are detached from what reality looks like!" but they don't even really know anything. As I said, it's the Dunning-Krueger effect.

To those shouting insults at you and making shit up, not worth even engaging imho, but I'd argue it's at least understandable where they're coming from.

Indeed, and this is why - as much as I grumble - some patience is needed with people. Nobody is born with a hammer in one hand and a sickle in the other, and I certainly wasn't. I could make fun of all the people who joined the Left only in 2016, when Trump made politics too difficult to ignore anymore, for being "late to the program", but I'd be making fun of myself also.

Sankara said it best: “As revolutionaries, we don't have the right to say we are tired of explaining. We must never stop explaining. We know that when the people understand, they cannot help but follow us.”