So apparently, since Ichio is Half Hollow/Half Shinigami/Half Quincy, his Quincy blood reacted to him swinging a sword near the soul king, and instead of attacking Ywhatever, he swung at the soul king, because Quincies hate soul kings. Granted, if it were just shinigami, how come he didn't attack his friends like... nonstop from the very start of the story? Maybe being soul king is like being the highlander.. there can be only one.
Alright, I'll stop analyzing this nonsense. This is my token abusive relationship where I keep coming back even though I know it isn't going to be any better.