Sounds like an issue of joint correlation. It makes sense that homogenous communities are better at building unions. Building solidarity with people who are different from oneself is more work than with people who are similar.
And it’s been found that exposure to different people and cultures reduces racist beliefs, so it also makes sense that homogenous communities would be more racist.
So the causal feature would be homogeneity, and the correlation between racism and unions would be effects.





Just in time for Grijalva to be sworn in
https://www.npr.org/2025/11/12/nx-s1-5606350/adelita-grijalva-swearing-in