Earlier quoted context omitted.
And Trump was called Hitler, Idiot, Psychopath and all sorts of other things. Presidents simply attract some amount of hatred.
Yes, to take your point further: instead of any of those names, for Obama people chose a racial slur. They could have just as easily used Hitler, Idiot, Psycopath. That would have been a better test of whether our society was in some post-race society that people think we're in just because we got one black president, once . If that doesn't make you stop and think, I'm really not sure what else will.
Actually it seems to me Nigger is a lot softer than Hitler. It basically means "black person I don't like because they are black". Hitler means "psychopathic mass murderer".
Besides, this is again the "there is an asshole in Kansas" line of thinking. Just because you can find somebody, somewhere in the universe who is an asshole, it doesn't prove that everybody is an asshole.