It is simple common sense. Most people do not operate on a level of altruism to where they will intentionally disadvantage themselves to get a fair deal for the other party. Most people do not have the temperance to not riskily overindulge on hedonism when it is readily available.

Why should we assume that men, the sex which has had an entire philosophical campaign to paint them as historical villains, who have had modern technology to increase their disadvantage, who nature itself made them less charismatic and appealing than women aren't facing any sort of injustice.

Truthfully I'm not sure what's the point of typing this out, considering most women will completely acknowledge this because it would make themselves feel like villains, but if you care about the truth you will acknowledge that within the dating sphere men are facing deep injustices.