Okay let's go back to before I was born when people still used IRC and let's say you hated someone else's IRC server. You can just use a program to flood their server with garbage messages. In order to try and stop this spam they first try and deanonymize where this traffic is coming from. This can be done by looking at the IP that these bots are coming from. Now they can gline you and the flood ends. Now let's say the internet didn't leak your IP deanonymizing you. What are they to do? They essentially are forced to lock down the server and whitelist it. They can not allow anonymous users to join or else risk just being flooded.
Stopping abuse has always been a game of trying to deanonymize users in order to try and ban the harmful ones.
Stopping abuse has always been a game of trying to deanonymize users in order to try and ban the harmful ones.