Because everyone here has tried. Dating apps get you 0.001% success rate except sometimes there are these ugly, obese single mothers.
To be fair if you are in your 50's, and lived in the Boomer era, and STILL never got a gf or anything like that, then you must be truly genetic garbage. Because the standards back then were much lower. Back then, an average man at least got his fair share, but these days average males get virtually nothing. Incel is a part of protesting that problem of rampant and extreme female hypergamy that goes far beyond the reasonable limits of a civilized society as we have known it for the past century.
The widely used expression "volcel if you wouldn't" exists here for a reason. It is used when a female or situation is presented (i.e. such as an average female on the street) where it would be ridiculous to refuse. Because it implies that there are some situations where the discrepancy between the male and the female is so extreme, that even most people here wouldn't scream incel at the guy for refusing sexual activity with such a grotesque creature (or one that WILL ruin his life if he gets too involved with her).