In the eyes of his black constituents, it was. And their interests are just as important as ours, even if we don't like them. When he was elected, just like Trump, he became the voice for all of his constituents, not just the ones that voted for him. Tough job, I doubt that any of us here would want a job like that. A million+ bosses is a tough audience.
I'd be thrilled to hear another solution when two evils are running...
Option "C" if there is one. If not, abstain. A nice letter to the "R" candidate explaining why he is not getting your vote.
"I know he's mean when he drinks, but he really loves me and the kids. Besides, he's the one taking care of us."
(Republican voters voting for more of the same)