99% of the stories about how Yngwie is such a jerk are related by people who weren't actually there. (Or in other words, they're mostly myth, spread by people who are caught up in the whole Yngwie-bashing game. Kind of trendy, like nu-metal.)
Almost all of the stories told by people who actually know him or have met him are that he's a normal, nice guy.
He's got a certain way that he wants things done, and if people don't want to do it that way, they don't have to hang out with him. He's interested in doing his own music, not somebody else's. There are a lot of us who are glad that he works that way, since we understand, and like, what he's doing with his music. Obviously there are going to be people that don't like that kind of music, or Yngwie's frankness. It's just really funny to watch the trendy Yngwie-basher lemmings frothing at the mouth every chance they get to spread a little more empty gossip.