My theory is that rich people and well-educated people vote according to self-interest, but poor and non-educated people according to identity. Billionaires votes for whoever lowers their taxes, academics for whoever secures them, often tax-funded, jobs, but poor people for whoever they like personally.

I'm positive that education was strongly correlated with voting in favor of unionization. This is something the left everywhere struggles with enormously. When poor people are too dumb to vote according to their own self-interest, the left's worldview falls down. The left then claims that poor people are brainwashed by capitalist propaganda. Yeah, maybe, but it can't explain completely disastrous results like this unionization vote.

Misguided people will claim that unionization is not in the self-interest of most workers. Those people are wrong as there are about a billion studies showing that unionization improves both salaries and working conditions. For example: https://www.epi.org/publication/briefingpapers_bp143/ The science is incredibly clear-cut and these workers who voted against unionization voted against their own self-interest.