Who is showing a double standard? Most everything I've heard from the left has been calling for his resignation. If anything, I think the left has judged him more harshly because he is a democrat.
Full disclosure: I went to a Halloween party in the early '90's dressed as Don King, black face and all. Some golf buddies of mine had called me Don King on occasion because of my hair, which was curly, black but starting to gray, and could get a little unruly on a windy course. They also called me Colin Montgomerie. If you need a better visual., take Colin's hair and cross it with King's. Guess I want be running for president.
I wouldn't do it now but I thought it was fine then. I also now think it is fine that I thought it was fine then but not now.