Until you can prove Warband ruined your video card (which you can't) you could be sued by TaleWorlds for defamation and slander.
And the guy was banned for a different reason: trolling. Because Warband doesn't burn your gaphics card out.
Let's look at the facts:
-How many reported incidents of graphics cards burning out have there been? Mine don't even get hot.
-There IS a framerate limiter, called vertical sync, if you want one that badly.
-He had an old, used video card that he bought off his friend.
All the evidence points to him being a troll who thinks that he's tough because he plays Call of Duty, and how dare Warband break his video card, it couldn't possibly be him or his friend, or just the card!
There is no evidence of it being Warband. This is also an isolated incident, if it was Warband, we would hear of other cases much more often.