What do people mean when they say that yaoi is fetish for straight girls?

Yaoi is a genre created by women for women. Real gay men are honestly rarely involved. Its literal purpose is to sexualize gay couples for the entertainment of girls. Also, traditional yaoi (Japanese manga) can be very toxic in the way it 1) leads to girls fetishizing and dehumanizing male gay couples 2) portraying the bottom as the "woman" and 3) fetishizing and normalizing rape and rape culture.

I do read some series (mostly Korean webtoons) because I think it's ok to read and enjoy series that aren't toxic if you understand that real life gay couples deserve respect and aren't your "sin babies," however since Japan and Korea (especially Japan) are very conservative countries where speaking out is not as tolerated as in other countries (ie America), it is hard to educate both creators and readers.

For me personally, I believe a lot of Korean webtoons are different from traditional Japanese yaoi in the way that they are generally less toxic and also often more realistic love stories, and there are a ton of good ones