The headline in the graph is completely misleading because it makes it sound like young men are abandoning sex voluntarily.
I don't think that is probably the case. I haven't been on the market for a very long time myself but from what I've read it seems that long-term relationships have more or less gone out of style among the younger generation quite some time ago. What I'm surprised by is that the change has been that quick.
The proportion of men between 18 and 30 who haven't had sex in the past year reached a minimum of 10% in 2008 and shot up to 28% in just ten years.
Women have also been affected by this but to a lesser degree because women between ages 18 and 30 don't usually have much difficulty in finding volunteers if they want to have sex with a man.
Here's another interesting graph. Notice how the proportion of men who report zero sex partners since they turned 18 is nearly the same as as the share of men under 30 who report no sex in the past year. This seems to hint to the two groups of men having a great deal of overlap.
My hunch is that this is all mostly linked to the popularity of apps like Tinder that caters to those looking to hook up with no strings attached. I don't think I have to bore anyone with lectures about the biological differences in reproductive strategy between men and women that gave rise to adaptations like men's greater sexual appetite and being less discriminating about the attractiveness of their partners in casual encounters or being more interested in casual encounters in the first place.
This is perfectly in line with what you can expect sexual liberation to look like. Because there is no scarcity of young men up for hooking up, most will get swiped left. The women on Tinder can easily be serviced by a relatively small group of men. Some women whose own attractiveness is a match to the men who are successful in the hookup game and who are not interested in hooking up themselves will find the men disinterested in relationships because they can get what they want on Tinder.
This isn't driven by young men. They are not, have never been and never will be in the driver's seat when it comes to trends in sexual behavior. The only exception is if a large percentage of them have been killed in a war like in the Soviet Union post WW II.
I don't think the women are ultimately getting what they want from this. The hookup culture will leave many of them lonely at middle age and regretting that they didn't focus on finding a good match for a long-term relationship when at peak attractiveness age. The divorce industrial complex isn't helping. Marriage has become a much less appealing prospect for young men in recent decades. But I don't think that is driving the trend visible in the graph above.