Of course, one needs a definition of "potentially" crafted specifically for the purpose of this specific claim.

Yes, good point: perhaps "socially permitted to be" is better than "potentially".

I agree that the parts of culture teaching (anyone) that rape is a socially acceptable action should be removed.

To be clear, the assertion is that some rape is taught to be socially acceptable. Violent rape and rape using illegal drugs is right out; we are talking about cases closer to the edge than the center, but which are still significantly harmful.

For example, it's part of the standard cultural romantic script that women put up a token resistance to advances, which men then overcome by being insistent and stubborn. This is social acceptance of rape to the degree that it instructs men to ignore non-consent unless it's sufficiently emphasized, or to put it another way, to the degree that it makes it more difficult for women who are non-confrontational to effectively deny consent.

From the simplistic "women good, men bad", we have progressed to a more nuanced perception of society "women good, men bad, but rich white women also a little bad, etc.".

I think this is also a strawman, at least of feminism as I've interacted with/participated in online. Privilege is an epistemological failure, not an ethical failure. To be privileged is not to be a bad person, it's to have incorrect or biased information-gathering skills regarding the experiences of various social groups compared to one's own.

I am not aware of mainstream feminists saying that [islam grants males rapists a safety bonus against consequences] loudly.

This isn't quite an isomorphic case: male privilege helping males abuse non-males isn't parallel to Islamic privilege helping Muslims abuse Muslims. However, if you're looking for general recognition among online feminists that Islamic countries have a lot of problems with gender inequality stemming from religious sources, then I'm very surprised to hear you say that.

And I think female rapists have it even easier in our society. Don't they?

Agreed.

According to this model, it would be acceptable to speak about "male privilege" or "rich privilege", and illustrate them with examples of rapists, but speaking about "female privilege" or "muslim privilege" and illustrating them with examples of rapists, is not acceptable, because it goes against the official black-to-white gradient.

This is a very good point, I agree. I have heard feminists address this by attempting to coin new terms, but I don't think it's working very well.