It's largely because a lot of western women think they have a "magic pussy".

Bear with me here.

When arguing with most western women, quite often when they start losing the argument they'll resort to personal attacks. Usually something along the lines of "I bet you're a virgin. No woman would ever sleep with you. Fucking incel/homosexual" etc.

It's a trope I've seen too many times to ignore. (I really like to argue. A lot.)

It seems to speak to the value they put on their own physical attributes. And as a result, in their minds, that's literally the worst thing they can do to a man is deny him access to sex.

It also suggests that they think masculinity is nothing more than sleeping with women and that's simply not the case.

So, you being disinterested/disgusted by the thought of having sex with them is quite a mind fuck because they're so used to having that power to lord over men they don't like or don't agree with.

It's a harsh realization that there's a segment of the male population that is completely immune to that particular insult.

Now, I'd suggest taking what I've said with a grain of salt. I'm just a random asshole on the internet, after all. But I think it would fuck most people up to recognize that their silver bullet is just a blank.