Nader is cozying up with the far right, yes. He's cutting into Kerry's support, yes.
It is still wrong to play legalistic games in order to keep him off the ballot. I don't doubt that Nader may have violated the letter of the law in Arizona, and maybe he doesn't yet qualify for the Florida ballot on a technicality. Great. Does that mean it's morally right to control ballot access?
Fuck no. Controlling ballot access is a method of controlling who can be elected, pure and simple. It is a way to say "minority opinions of a certain size don't count." I dislike Nader vastly, but let the hypocritical bastard run.