This doesn't just apply to race. The whole "trans people in women's bathrooms/sports" panic was another example of people being told that a tiny minority of people are a huge threat that we all need to focus on, while we were being screwed over by a kleptocracy. Same with "Antifa."

And it worked. Politicians do this because it works.

True, the right used this against the left because this issue, and particularly the aspect of males in female sport, highlights a set of absurd beliefs that are unfortunately quite common on the left. Political parties pushing ridiculous views tends to be a vote loser, even if the impact of these views when translated into policy is relatively small. It's like how a flat-earther politician would put a lot of people off.