I don't mean this in a "some people are just so shitty they don't deserve love" kind of way, but in a biological way.

At the end of the day, humans are still animals, and as such are still subjected to natural selection. In the simplest terms, natural selection is nothing more than differential reproductive succes. Some people get laid, some get laid a lot and another portion never gets laid at all.

Many people try to become the best version of themselves, but still fail to find a partner. Maybe it's on them, but I believe a lot of guys and gals have just been dealt a bad hand from the start. Not everyone was "meant" to have a relationship/have sex, and trying to deny this is like denying nature itself.