George Lucas unironically wrote a great story about how ineffectual liberalism is
everyone hates The Last Jedi because it's a dog shit movie, it's not that deep.
Interestingly their system of allocating votes per planet instead of votes per population probably led to this impasse just like in the USA. The slaver planets would be able to veto any motions to abolish slavery with their disproportionate representation. People on Coruscant are totally fucked and get like one millionth the vote as a slaver on Tatooine.
The republic also treated droids as second class citizens and slaves despite their apparent sentience
Even as bad as that is, you're making it out to be better than it actually is.
Not every planet gets a Senator. There are a lot of member planets that don't have them. Also, for planets with multiple distinct populations that have a Senator, all the minority populations get is a non-voting Representative (e.g. in episodes 2 and 3, Jar Jar is the non-voting Representative representing the Gungans, while Padme represents the humans of Naboo and also the planet as a whole, as the sole one who actually has power)
"Slave Power" conspiracy in the Galactic Senate. Stop making me want to write weird political Star Wars fanfiction
I could be wrong, but I believe slavery was banned in the Republic, but there were planets outside the Republic’s reach, like Tatooine. I don’t think Tatooine was a member of the Galactic Senate for example.
You could certainly argue the Republic should’ve done a better job fighting slavery outside of their territory, and that as Galactic hegemon it was ultimately their responsibility, but within the Republic slavery was banned.
Also the droid thing, droids were fully treated as slaves and no one even questions it, not even the heroes.
The trade federation didn’t, right? Could swear they had leaders who were liberated droids.
The Confederacy had liberated droid leaders sure, but the Trade Federation were real fuckin goons about it.
I think someone came up with that line as a way to metasplain the change in demeanor of the battle droids between film I and II, which was really done to sneak in jokes and sell toys.
You could argue that as the war heated up and with such short life expectancy it probably wasn't a priority blah blah, but this isn't supported by the films anywhere and keep in mind Federation droids were soulless automatons juxtaposed against the Naboo's disposable astromech droids and Anikin's homebrew threepio that are definitely portrayed to have some kind of personality or soul in the film.
E: also IIRC there are throwaway goofs in the films where battle droids mention turning themselves in for a memory wipe
planets outside the Republic’s reach, like Tatooine
Tatooine is a part of Hutts Space which is a independent galactic state from the republic, however the republic did had things like indentured servitude which was basically slavery
Also of note: obi wan literally has to be forced to get off his ass and go help people by his friend who’s actually out there doing good.