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

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

But other than that, not really

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

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

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

آپ should tell them the truth.... maybe they feel like its a slap in the face to them. They are wondering. Dont worry آپ are not the one at fault... it would though be a good idea to tell them why آپ have changed sides.?? One thing for sure آپ 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 آپ stay around people who make آپ 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 آپ down. But if they ask آپ that again, explain why. Hopefully, they understand. And they might stop doing whatever it is that's making آپ feel like shit. Sometimes, آپ have to point out a flaw.