Coming from someone who's got ample experience with all three, (DMT is also the active substance in ayahuasca, by the way): That's one hell of an interesting question! I can't say I know... I've always been a pretty decent person. Good, but of course flawed in a lot of ways... And it's always showed me that, and helped me work on all sorts of things that I've needed to work on.
I think it's hard to take such heavily mind + soul manifesting, introspective drugs like that, especially if done in a ceremonial context, and somehow NOT see what you are... The question is, would it bother you, if it showed you that you were a bad person? I think it would probably bother MOST people... Like with me, for instance, in spite of not being a bad person, I was shown that I really needed to treat my mother better... To be more forgiving and less petty. To start telling her how much I loved her, and start appreciating her for who she was! Rather than constantly getting on her case for not being what *I* wanted, (and maybe sometimes needed), for her to be... Lesson learned. We've got a much, MUCH better relationship these days! :)
But yeah... There might just be some people that are so far gone, and so totally self-absorbed, they don't even care if they hurt people! They might even be swallowing ALL of their own crap, and buying into ALL of their own worthless excuses! Can't say I've ever met those people at an ayahuasca retreat, though. I suspect it's not their scene... Go figure. :-P
Anyway, I suspect some of them COULD still have a powerful transformative experience that made them change their minds about it! That made them WANT to be a good person! That made them actually start caring about the lives of others... That made them want to give and receive love... I know my own psychedelic experiences have very much strengthened that part of me, for one! But I always had intense emotions, and some level of empathy, to begin with. It just made me love deeper, made me care more, and further increased that empathy by quite a lot. And.. having extremely intense, direct spiritual experiences, where I fully dissolved into what God is, to me, (if you want to use that word), was a HUGE freaking part of that, for me!
So... maybe trigger a massive ego death experience, or some kind of other powerful mystical experience, in sociopaths..? I really wonder what that would do them... Please feel free to share your stories, if anyone else has ever been through that..? Color me very deeply curious. ;)
Anyway, in the end, I guess it's partially a matter of what's in you, and what places your brain can or cannot go to, and partially a matter of how much you take, how much you're able to surrender, and how deep you go.... I'm sure people like that can easily take small to medium dosages, or maybe even some fairly high ones, and still manage to resist that sort of transformation! By not going there, and just surfing the waves, rather than getting pulled underwater to drown, and fully having to face everything they are.
Unfortunately NOT evil. :-P