"Off Topic - Doesn't fit elsewhere? It goes here. "
I pity you if you've spent a half hour looking for the correct forum and didn't see that.
Do you run/own/administrate these boards? If so you can easily block thier account, IP, hostname, or a variety of other things. If you don't run the board, maybe the person that is in charge doesn't share the same opinion as you and has no problem with this person. If they did, logically, they would do something to remove the person's presence from their board. The truth is you can't stop someone from having an opinion, and if it's different than yours, I suggest you just learn to deal with it. That is the solution I suggest for you, learn tolerance. It will do you a great deal of good in your life and be very beneficial in your social endeavours, as well as the work place environment. For it is tolerance that allows people like us to deal with people like you.