I think online dating makes this significantly worse for guys. If you're meeting women IRL height is a lot less of an issue but online just that number becomes a huge barrier that you simply cannot overcome. Women who you would either have not interacted with much or would have been okay with your height if you had met in person will go out of their way to insult your height or wordlessly unmatch as soon as they find out how tall you are. It takes a lot of mental fortitude to keep your head up and realize that it's just a false impression based on the messed up dynamics of online dating and I can see how it could just destroy a guy's self esteem completely if he didn't realize that or couldn't keep the fact that it's an illusion in mind.