Fun fact: It's not all about you.

If they abused you then yes, they should stay away permanently. But casual friends always come out of the woodwork and if an apology comes with it, then that's great. Life is far too short and a lot of times people gain an immense amount of closure from catching up and hearing an apology once the muddy waters have cleared.

It's also a huge learning curve. If you did them wrong and they re-enter your life and apologize to you, as a way of clearing the waters and showing respect, and you can't return the favor despite being in the wrong? Then this is a lesson taught. The person hasn't emotionally matured nor changed. So this is confirmation that the door should remain shut. There's a lot of peace that comes with this.

Believe it or not, pushing everything so far down that you're re-triggered upon speaking to old friends is not their failing, it's yours. Nor is it healthy to live this way.

It sounds like you've not processed a bunch of stuff and their reappearance has triggered you. You should be indifferent if it was years ago. If you're not, you've not done the work to move on like they have done.

Granted, some things are unforgivable but your examples don't warrant your extreme reaction. If you don't want to be contacted by them - block them indefinitely and ignore their messages.