It has to do with culture, politics (obviously), and race imo.
There was a time in this country where the great majority was white.
At first the democratic whiteys represented the lower echelon of whiteys (younger folks, working class + KKK types). Then by the 60s it morphed into something else. The whiteys that were into counter culture, hippie culture, and the feminists aligned with the democrats.
Non-whites starting coming into the country in significant numbers by the mid 60s and these non-whiteys aligned with those hippie whiteys. Put it simply, non whites preferred the democrat whiteys simply because these whiteys were more liberal and less concerned about non-whites. These liberal whiteys were more concerned about using drugs and having lots of sex because of counter-culture/feminism in the 60s and 70s. Fast forward to now, and it includes radical blacks and mestizos that are quite rabid. These are the type of people that tolerate people regularly getting stabbed to death or shot. Because not tolerating it would be racist against blacks and browns. It's quite common for people to stab/shoot people to death in democratic shitholes and only serve 12-24 years. At times, far less than that with good behavior.
Later as time went along, the working class + KKK type of whiteys went over to the republican side. The republicans represents the elite White American Anglos and everything they stand for. Which ironically, could care less about po white trash.
Until Donald Trump came along. The Donald was basically a democrat. His base, even until today, are po white folks of the midwest and south. Basically the meth'd out, bombed out, ignored, and forgotten about communities in the flyover states. But the Donald ran on the republican platform simply because he knew that the po white folks that were once in the democratic party simply switched to the republican party enmasse.
I will end by saying that Asian American men have absolutely no business voting democrat whatsoever.
The people that are most strongly democrat and have every incentive to vote democrat are namely, white feminist women (degenerate slobbish white women, the niggers of women basically, using their gender and victimhood to gain whatever advantage they can), self hating low-mid tier asian american women that are into low tier white men, low tier beta white males who struggle with white women and are into asian women (and other ethnic women), self hating black men into non-black women, black women in general, criminals, illegals, rabid and aggressively progressive, anti-colonist latinX people, homos, and jews (jews dislike religious regular american whiteys because they're like a huge thorn on the side of jews). Basically the democrats consist of the worst of the worst types from every race with the situation made even worst with a dog eat dog type of scenario where everyone is looking to get theirs at the expense of everyone and society as a whole. A total utter shit show basically. The republicans, although not perfect, are usually more fare and indeed, the nonwhites that vote republican usually seem like better people overall compared to their democrat counterparts.