"Bad faith"
Talk:Srebrenica and User talk:129.125.102.126 would be a good start. That's the IP he used previously (while spouting the same "pseudonym" name calling) and that one was blocked too. So this is in fact his second ban in the past year. Also, in case you weren't aware yet, he's been permanently blocked from English and Dutch Wikipedia already, and I think he even got a global Wikimedia-wide block for his behaviour. So it's not like he came here with a clean slate, even if we did try to give him a chance. He just didn't seem interested in getting on anyone's good side. I don't think he's ever going to change, judging from the longevity and wide scale of his past abuses, so the block is a decision along the lines of "are we going to endure it forever, stop it here and now, or let him do it some more and block him later?"