I'm reading this letter and I'm thinking, "I agree with that," and it turns out to be our own Gary Crum.
Good take using the extension of whether the real men name calling applies to older guys.
Some people still believe that for one to be a valid human being one has to be a "real man" or "act like a woman." I suspect they think that there are god given or nature prescribed behaviors that come with being either male or female (having a baby one exception). I tend to believe that we are more socialized to act like a male or female. 
But on a deeper level the charge that one is not a real man is just as sexist as calling a woman too masculine. Many of Trump's supporters place people in neat boxes of real men or real women. This is also why so many of his supporters can dismiss Trump's boasting of sexual conquest and his pride for having screwed instead of fighting in a war because he risked getting AIDS.
Losing the real men dichotomy scares some weak people who hide behind those labels.