Trump is spouting racist rhetoric popular a century ago, like "racehorse theory" — see Trump Praises Good Genes for Haaretz's comparisons to the Nazi era.
Trolling Techniques: (1) Outrage —> (2) Innocent Echo —> (3) Attacked
(1) Another heavily used technique in modern politics is saying words that don't sound offensive in an offensive manner, until anti-racists hate the phrase and get rightfully angry each time they hear it. (2) Then people who aren't paying much attention — unfortunately that's an awful lot of us, a lot of voters — are curious about or like the actual meaning of the words. They say the words or ask about them ... (3) and anti-racists assume they are trolls and attack. This divides people who were apathetic about racism or are young and new to politics with the racists and away from the anti-racism team. They keep learning about the issues from the people who seem to be agreeing that of course all lives should matter. — This tactic usually overlaps distracting conversations from the core point like turning a video of a police officer killing a black person into a weird and meaningless tangent about dictionary definitions. — This tactic is related to dog whistles. Unlike past dog whistle politics, this is similar to handing out a dog whistle to someone who doesn't realize they're blowing in a dog whistle, causing them to get a reaction they didn't mean and don't understand.