You make a point, but the problem is that the only reason a lot of men will accept is "I have a boyfriend." Women will get harassed non-stop unless they use that.

Stop right there. The entire problem with this discussion is it's an attempt to inject gender politics into gender relationships. Your sentence is reversible: "the only reason a lot of women will accept is "I have a girlfriend." Men will get harassed non-stop unless they use that."

The issue is clouded by the simple fact that even in Our Enlightened Era, men remain the pursuers and women the pursued. That's the paradigm we're all used to. The context of this discussion is "women who wish to go to locations that exist largely for hooking up without having to hook up." That's pretty fucking empowered right there, but somehow men are oppressing women if they don't encourage women to be bitchy in their response. Again - put the shoe on the other foot.

"hey, handsome, can I buy you a drink?"

"No."

"Uhh, okay. Was it something I said?"

"I'm not interested."

How do you think Jezebel would respond to that?

So take it out of the dating milieu. You're walking down the street and a dude asks "Hey buddy, spare any change?" Two possible choices are "Sorry, man, no cash" and "get a job." If you say "sorry man, no cash" then you can end the conversation with no hurt feelings. If you say "get a job" you can end the conversation by asserting your belief in a merit-based economy.

Also by being a douche.

Or: You're hanging out at the club and someone asks "Hey, man - spare a cigarette?" Two possible choices are "Sorry man, don't smoke" and "buy your own." If you say "sorry man, don't smoke" you can end the conversation without hurting any feelings. If you say "buy your own" you've just engaged someone to fixate on your evening sucking for as long as you're in sight.

You know what's keenly anti-feminist? Ascribing chauvinist motives to strangers looking to flirt simply because they're looking to flirt. You know what's also keenly anti-feminist? Arguing that rudeness is an acceptable vehicle for feminine empowerment. But you know what's the worst? Arguing that feminists aren't being feminists if they're polite, while arguing that women who are polite aren't feminists. Because it leads to bizarro-world statements like:

I actually have used the "sorry, I'm not interested" to women in bars before. Of course, it's phrased a little differently, but I don't mind using "I have a girlfriend" either, because, unlike what women face, the entire world I live in isn't controlled and dominated by the opposite sex.

In two sentences you said you've done the same thing, only different, and then argued that women get to be rude because the "entire world" they live in is "controlled and dominated by the opposite sex."

Look. The glass ceiling still exists. Women do not have total equality. But this is some straight up Lysistrata shit here. And it's fucking stupid.