It doesn't matter how hard I study Facebook's terms and conditions, I still can't find the bit where it says: "Like Humpty Dumpty, Facebook is at complete liberty to interpret the words used in this document in any way it sees fit." And yet that's obviously what Facebook executives have been doing: making words mean what they want them to mean, or else they'd have removed the pages that promote rape and other forms of violence against women months ago.

The specific clause in Facebook's statement of rights and responsibilities that's supposed to protect groups against violence and hate speech instructs the user: "You will not post content that: is hateful, threatening, or pornographic; incites violence; or contains nudity or graphic or gratuitous violence." However, Facebook has now defended the numerous pages that clearly violate these terms by claiming: "Groups that express an opinion on a state, institution, or set of beliefs – even if that opinion is outrageous or offensive to some – do not by themselves violate our policies." Which is strange, because if a page entitled "Roses are red, violets are blue, I've got a knife, get in the van" isn't hateful, threatening or gratuitously violent, I don't for the life of me know what is.

It was back in August that feminists first began to notice the proliferation of pro-rape pages on the popular social networking site. Two months later over 176,000 people have signed a US-based petition calling on Facebook to take them down, and nearly 4,000 people have signed a UK-based petition calling for the same. The Facebook pages, such as the one cited above and others that include "You know she's playing hard to get when your [sic] chasing her down an alleyway" still remain.

Facebook's initial response to the public outcry was to suggest that promoting violence against women was equivalent to telling a rude joke down the pub: "It is very important to point out that what one person finds offensive another can find entertaining" went the bizarre rape apologia. "Just as telling a rude joke won't get you thrown out of your local pub, it won't get you thrown off Facebook."

And in some ways they're right: telling a rude joke probably wouldn't get you thrown out of your local pub. I'd suggest, however, that propping up your local bar while inciting others to rape your mate's girlfriend "to see if she can put up a fight" would not only get you thrown out, it would in all likelihood get you arrested as well. Still, at least you could log on once you got home and post your offensive comments on Facebook instead, safe in the knowledge that they wouldn't do anything about it.

What Facebook and others who defend this pernicious hate speech don't seem to get is that rapists don't rape because they're somehow evil or perverted or in any way particularly different from than the average man in the street: rapists rape because they can. Rapists rape because they know the odds are stacked in their favour, because they know the chances are they'll get away with it.

And part of the reason rapists get away with it, time after time after time, is because we live in a society that all but condones rape. Because we live in a society where it's not taken seriously, and where posting heinous comments online that promote sexual violence are not treated as hate speech or as content that threatens women's safety, but are instead treated as a joke and given a completely free pass.

By refusing to take these pages down, and by resorting to such a ridiculous and quite frankly offensive "rude joke" analogy to justify their decision, Facebook executives have made absolutely clear where they stand on the issue of gender hate crime. It's fine to post hateful or threatening content on their site, just as it's fine to post content that incites violence. Well, as long as it's primarily aimed at women, that is.

• This article was commissioned after a suggestion by cbarr