[fancyketchup]

As a public figure, MLK ('s estate) has greatly reduced right of publicity, so I'm not sure how you think that would come into this. You are allowed to criticize celebrities. Even in California, MLK's personality rights wouldn't survive his death anyway.

As for Trademark... what is the trademark here, and how would anyone be confused by an MLK-Hitler poster? I don't think anyone is going to buy an MLK-Hitler poster thinking that they are getting MLK-brand doughnuts (or even MLK-Hitler brand doughnuts).