Whether men currently are or not gatekeepers of sex is irrelevant. They SHOULD be.
Women have been forced into that position by men who are abdicating their role as protector of women by not being gatekeepers of sex.
... and it should rain sprinkle doughnuts, and unicorns should fart rainbows, and the rent should always be due tomorrow, and...
"Earth calling metmom! Come in, metmom!"
You are demanding behavior that runs totally counter to Human Nature. That might function in some utopian paradise dreamt of by Sir Thomas More or envisioned by C.S. Lewis. Some post-scarcity society inhabited by toga-wearing saints and ruled by an enlightened philosopher-king. But NOT in the real world (unless you are talking about some oppressive Islamic country where women can't be seen in public and loose daughters are stoned).
I SHOULD be able to stagger down the back alleys of Harlem at 3 a.m., drunk as a skunk, with hundred-dollar bills sticking out of my pockets, shouting "N*ggers!", with impunity, but I couldn't, with a straight face, introduce that as a basis for serious discussion of societal mores and normative behavior in 21st-century America.
Women have been forced into that position by men who are abdicating their role as protector of women [...]
This is hilarious! We have "abdicated" our role as women's "protectors?!"
"Chivalry is dead! And Feminism killed it!"
Men have not abdicated their role: Rather, it has been wrested from them!
Any man foolish enough to attempt to rush to a woman's aid in today's world is liable to run a-foul of Human Resources, if it happens at the workplace. If it happens in a public place, he might be let off easy with a mere "I'm a grown woman and can open a door for myself!"
Let me take a step back and acknowledge that, historically, men were indeed the gatekeepers of sex and protectors of women - but only in the sense that fathers had total dominion over their daughters, and were widely recognized by society as having the right to intercede, control, admonish, and even punish them for the slightest deviation from expected behavior, right up until marriage (which, in most functioning cultures, the fathers and mothers would arrange). But let's be realistic: Barring a nuclear holocaust, that world is never coming back. The Nanny/Welfare State has supplanted men as providers, and the Police have supplanted men when it comes to physical protection.
For most of their late-teens and early-20s, most decent men* are struggling to find their footing in life, and to make sense of the modern dating world.
*I am explicitly excluding ghetto trash and the like. Instead, I am limiting my scenario to the kind of men whom you would probably say were capable of being "saved," were still amenable to rational persuasion, and the like.
These "average" men have a low SMV (Sexual Market Value), and can hence only react to existent market pressures. Rather, it is the women (with an initially high SMV) who get to establish the narratives, set the rules, dangle the enticements, etc. Any "average" man who, in this environment, would step forward and announce: "I have not abdicated my role as Protector! I will withhold sex until it is sanctified by the Holy State of Matrimony!" would be laughed out of the room.
What you don't seem to realize is that the modern dating market is akin to the Prisoner's Dilemma - a situation in which any one individual or minority of upstanding and honest individuals is automatically at a disadvantage / is actually punished for righteous behavior. In fact, even the majority of the population could sincerely wish to adhere to elevated moral principles, but will nevertheless suffer negative consequences for doing so - because a few "bad actors" suffice to ruin everything.
Now, don't get me wrong: I am not saying that the answer is for young men to abandon all morals and dive headfirst into the cesspool that is the modern dating market.
Regards,