I will give an unfiltered answer here, and apology in advance if it sparks an offensive connotation.
To begin with, it all starts with the Filipino perception that a "greener pasture" is a place somewhere outside the Philippines. I'm a Filipino, and I admit I am not different with that kind of mindset because.. it really is. Life in the Philippines (if you're poor) is very hard.
There are Filipino professionals who practiced their professions overseas but mostly, we land a job that doesn't match our qualifications (if you're not a graduate in any medical field). Plus processing a work visa to work outside the Philippines, say, western countries, is not easy, and costly and most Filipino job hunters don't have these requirements.
And so, yeah, to make it short here comes the fiancé visa. Which is easier to obtain for an Asian woman if she found a foreign suitable partner. A fiancé visa (K-1) is far more accessible and straightforward if you have a U.S/ western partner, as work visas require an employer sponsor. Although, work visas offer permanent resident paths and immediate employment, whereas a fiancé visa requires marrying within 90 days and a lengthy wait to get a work permit.
I never saw an actual demonstration of extreme feminism but I think that plays a big factor why western men shift their romantic interest toward Asian women, plus of course, several factors like cultural stereotypes, relationship priorities, and physical preferences. Western men flocked to Asian countries to look for a suitable partner and bring home their wife and establish a life together.
I won't ignore the idea that there's feelings involved. There is, of course. Feelings developed overtime. But let's be realistic here, for a Filipina woman, western countries are a land of opportunities and they will grab every chance to get there the easier way, and that is to find a foreign man. In some cases, the foreign man, who usually a retiree, wants to settle down in the Philippines.
The main reason I see why some Filipina women wanting to leave their country and settle overseas is it is easier to help their family back home. Once the Filipina wife granted a, say, a US citizenship, it will be much easier for her to help her family back home or bringing them to work there.
