IP ban involves a lot more people than just the person in question.
Perhaps. But unless you ban the IP, the person can just endlessly change names, i.e Vashgun, HEWG, Ihategod, etc.
I was banned by a well known Christian website's chatroom for asking if they had a forum to challenge the fairness of a moderator's decision. They said no and then proceeded to make some terrible comment about members of the board. I can't remember what she called them verbatim, but it was something like "peasants," or something extremely derogatory and uncalled for, especially for an avowed Christian. I responded, "Don't you think that's a little fascist?"
Then they banned me.
Literally, that's all I said.
Point is, they banned my IP address, because I wanted to see if I could get back in using another name. Very effective.
"It is better to shun the bait, than struggle in the snare." -Ravi Zacharias