You are correct and you are also arguing with an idiot. Thought I'd point that out.
Note, however, that as far as 2018 is concerned the black vote is a negligible factor. Even if Trump can win black voters, convincing them to go out and vote for their local Republican is dubious. It can be done possibly, but it will take a major new communications/branding effort from the WH and so far that is definitely not part of the Trump WH skill set.