Let`s us say that a exchange got hacked, Would there be anyway to ban those bitcoins? like blacklist the stolen coins so they cannot be used on the network? I know about going back in time with consensus of the network to a earlier block or forking and using that new chain, but could you just not ban the stolen coins? I mean make a way to do that?
you would first have to prove it that it was your coin in the first place. And that method has to be waterproof as well.
otherwise what is stopping a random person from claiming your unstolen coins?