I mean that is a pretty massive generalization. Sure there are plenty of instances where gay men are depicted as "safe" in some wider pop culture that said people often bring up fiction as a big reason for why some people come up with these ideas they are another sex. Anyone who has spent time going through yaoi or MLM fics knows how common rape and other forms of morally dubious acts are commonly depicted. You got a mix of both people writing stuff like this but women seem heavily drawn to it.

It's not much different than other fantasies such as AGP you just want to be what you are attracted to or you have other issues with self esteem, your body etc where it allows for you to self interest into a fantasy world. Not saying women also haven't been drawn to those more innocent depictions and that is becoming more often associated with said fiction but it's hardly a universal thing and in my experience it's pretty divided amongst women into it.

To argue every women is into gay men because they feel less threatened I don't really always agree that is the case. It's pretty easy to attribute it to the same reason many MTF claim a lesbian identity and want to sleep with lesbians. They are attracted both to the fantasy cooked up in their mind and the sense of validation that will help their sense of self image.