You've gotten a few answers to this, but one that I didn't see is that it's simply someone with anxiety dealing with a lot of pressure, justified or otherwise.
There are a lot of unhealthy stereotypes ingrained into people (mostly men, though) through the media, parenting, peers, etc about how we're supposed to interact with potential partners. There's a large stigma around not having sex frequently, being single, or being a virgin that means that you, especially at an early age, are a failure of a man and should be treated (and will be treated) as such.
This is compounded by the fact that this is partly true - sex is a large part of our culture (as Americans, at least) and we have such a warped view of it. For young men, it's thing that you have to do as a your own trial of manhood and by contrast for young women it's this thing that you have to try and avoid and safeguard. There are barely any good resources for sex education (schools either go too far or not far enough) and a lot of young men take cues from literal pornography, which really complicates the issue. I'm no porn-hating puritan, but it's really not a good resource for learning how to participate in sex.
Additionally, there are virtually 0 resources for actually building the relationships that one would need to build to have and maintain a normal sex life. What passes for "resources" out there are horrendous wastes of time (a.k.a Red Pill shit, Pick Up Artistry, or advice for Men from Women) that lead to some horrific behaviors. This is on top of the prevailing sense of entitlement that is synonymous with the "millennial" generation.
We basically throw all this at kids (mostly men, but there are nice girls too) and expect them to figure it out - but some kids just can't handle the pressure. The air of desperation that comes from them comes from the fact that they literally think if they can just figure this out, to be "normal", that their lives would literally change right then and there.
This has always been a thing, but technology advances have made all of the worst parts of it much, much worse. You can get bad advice much easier, you can be in constant contact with people when sometimes you really shouldn't be, you have much easier access to pornography than ever before, it can be really hard to escape from once you've dug yourself in.
Not that it's an excuse, mind you, but we really throw a lot of people into the meat grinder with no real preparation and are shocked when some people don't "get it". It's society's lack of preparation that has morons like this paying $30 for some e-whore's bath water instead of being able to look at themselves in the mirror and figure their shit out.