If bitcoin is the only crypto currency that exists then yes you are right. But there are already ways to work around such a ban (like swapping to monero). In se

If bitcoin is the only crypto currency that exists then yes you are right. But there are already ways to work around such a ban (like swapping to monero). In several of the recent hacks, big exchanges did try to ban addresses but were not successful in stopping the laundering. Or at least that is my understanding right now.