If I walked away from somebody who made me feel like absolute shit, am I the one to blame?

Ты should have explained how Ты felt, to give them some closure.

But other than that, not really

Nothing's your fault; Ты should always walk away from people who make Ты feel like shit because they're bad for Ты and Ты should surround yourself with positive people. I think Ты should be straight with them now though and tell them why Ты stopped hanging out with them, for closure.

Ты have no obligation to be nice to someone who does nothing but hurt you.
Now, if that person does do nice things for Ты once in a while, he/she may be trying to be nice but is having a hard time with it. Ты should do what Ты think is best, but try to think about it before Ты do it.

If your relationship with someone is destructive then Ты have every right to walk away. But I think Ты do owe them an explanation. Just so that Ты put it all behind Ты and Переместить on. Even if they respond badly to what Ты say, Ты shouldn't feel bad about it because Ты have done your best to resolve the situation.

Ты should tell them the truth.... maybe they feel like its a slap in the face to them. They are wondering. Dont worry Ты are not the one at fault... it would though be a good idea to tell them why Ты have changed sides.?? One thing for sure Ты do not need to feel guilty because that will just eat you. its human nature to change so its fine.

hell to the fucking no

No way! Why should Ты stay around people who make Ты feel like shit? That's only a stress booster not to mention it would be super annoying to have to face someone who always shuts Ты down. But if they ask Ты that again, explain why. Hopefully, they understand. And they might stop doing whatever it is that's making Ты feel like shit. Sometimes, Ты have to point out a flaw.