A lot of it is based on how society and gay culture especially focus so much on hypermasculinity as the ideal. Asians are freqeuently emasculated or ignored in mainstream media and this is exacerbated in gay culture. No fat, no fems, no asians is a common trope, and this has lead to the alienation of gay asians in the community and the appeal of white men as a trophy to win over.
There is a lot of self-loathing and white-chasing in the gaysian community. A lot of self-professed potato queens chasing after white men, but unfortunately, most white men aren't into asians, so they end up settling for older, unfit, less attractive white guys who are more likely to hook up with them.
I no longer get frustrated if a white guy tells me they're not into asians. They like what they like, I'm not going into the whole drama of preference vs racism, I'm not going to change society and I learn to move on. I personally find raceplay helps me navigate the feelings of alienation I get, explore and play around my attraction for white men, and get a sense of catharsis over not feeling like I'm attractive enough, or even at minimum, just seen or acknowledged in the gay community.