Rosie said that he is no beacon of morality having gone bankrupt several times which isn't true, remarried, etc. She attacked him without personal provocation and he doesn't sit still when someone attacks his credibility or lies and so he went after her. He said, "I will probably sue her" (for slander).
Rather than learning from that and shutting up, she continued on her blog and called him a PIMP. He didn't like that either. I find the whole thing entertaining.