I'm not sure on this, but weren't transgender men not recognized at the time "penis envy" was thought up?
Because I think that would explain it pretty well

I think it was stupid and insulting to women the way it was used when the phrase was coined but on the other hand I totally do have it. I think penises are so cool and I love to have one, even just to try it for a little while lol. I don't think it's not something that is related to lesbianism or that you could say "everyone" has, but I'm sure I'm not the only one