+2
Ok. I'd mention :
1) The Taxi movies. Luc Besson bull**** at its worst (sexist, racist, trying oh so hard to look and sound cool, just embarrassing).
2) Salo, of course. No ill intent, but deliberately disturbing representations of dehumanizing sadism in context of fascism. It denounces what it presents though.
3) The whole torture porn genre (Cannibal Holocaust, Saw, Human Centipede, etc) which is a mere exploration of pain, both as an on-screen exorcism of latent fears ("yes ! this is exactly what is not happening to me !") and some juvenile sadistic glee ("hey what if, what if we did something even worse to someone, I have an idea for a film"). The viewer's position in those fantasies is ambiguous.
4) Nazi propaganda. Jud Süss, for instance, or the Leni Riefenstahl odes to fascist values (still fully embraced in various mainstream forms nowadays). By extension, you can decide to set by yourself the threshold of abjection on the vast continuum of propaganda movies debasing whichever minority or otherness to whichever extent, an axis starting from these historical extremes and going to the most accepted ones at the other extreme (the war or vigilante movies which racialist, xenophobic, homophobic or culturalist implications we now tend to forgive or consider hilariously cheesy). Where's the limit ? Somewhere in-between, I guess.
5) The killer inside me is an unsettling movie about an extreme case of manipulative violence and gender dominance. Features a few instances of "Yeah okay got it. The point, though ?".
6) Birth of a Nation, of course.
7) Various modern propaganda films presented as "journalistic" and "neutral", yet transparent platforms for extremist political groups, campaigns, conspiracy groups, religious fundamentalists or white supremacy authors (from D'Souza to Southern). Of course, beyond mere misinformation, evaluating the abjection of it may depend on your own worldview and ideology.
8) Snuff movies, were they a thing for real, or were they like iron maidens ? And if fake, but believed true by the public who enjoyed them, that's still something.