The lie is that your worth as a human being is determined by your ability to attract, secure, and keep a sexual partner and that without being able to obtain that metric for yourself, you have no value as a man and your very manhood is called into question.
This is a bullshit lie based on propaganda. I cannot stress or say enough how much this is bullshit. Remember Biff from Back to the Future movies and how he kept getting buried in manure? This is the level of bullshit we're talking about. Or chicken farm levels of bullshit that can be smelled for miles around. I won't even bring up pig farms because it's sorta close to lunchtime and I don't need that in my head cause I brought a BBQ Pork dish for lunch. Proprieties and all.
Let's just talk about some examples that highlight how this idea is obvious bullshit.
Priests. Are you saying that because they chose a vocation that requires celibacy they have no value as men?
Gay men and Transgendered persons. Don't you find it odd that the only people who fall down this particular rabbit hole are CisHet men? Nobody else has a problem finding their self worth or purpose in life or based it on the "acceptance" of someone else. There's a reason for that, you know. It's because the whole idea is ridiculous.
Time. Say you married young, right out of high school but your wife died tragically young. No one else ever looked twice at you the rest of your life. By your own criteria you've been validstes as a man, you were chosen. You still spent the bulk of your life sexless and alone. You have no children and youre just going to work day after day living that drearys existence you fear. But you've been validated so nownthat misery of being akone is somehow tolerable or lessened or wirth it? What???
I've got more but I'll have to return at lunchtime.