I can't speak for anyone else but I'll speak for my friends and people around me. I'm a woman and not Asian for context. I noticed that among my friends the ones who are least/not attracted to Asians are the ones who have little to no interaction with them and do not consume media(whether unknowingly or not) with Asians in it

I would say when I was younger I personally wasn't attracted either but it was because where I'm from the only type of Asians we saw on tv were Jackie chan and Bruce Lee. I wouldn't like that type of guy even if he was another race but at that time it made me think that was how Asians were like, albeit on a subconscious level. So I think the reason for many women is exposure and positive portrayal of Asians in media

I should also add that my answer mainly focuses on East asians since my country has a lot of South Asians so I grew up around them