The Princess Half is not gender specific, men can't win but they still get a finisher's medal. It isn't like they don't let any guys race. Same with the Tinkerbell Half.
I agree with PPs that the difference with these Disney female-oriented races
like the Princess and Tinkerbell is that women are accepted as full participants with full awards and honors, not relegated to second-class status.
In what Disney race do women not get full awards and honors? AFAIK, every other Disney race has awards for both men and women*. The Tink and the Princess have awards only for women.
Actually, I would argue that they don't really let guys race the Princess or the, presumably, the Tink - they let them run it. But, if a 60 minute, 10k time puts a woman in corral A, and my 40 minute 10k time puts me in corral B, I can't really "race" it - because I will spend the first two or three miles of the race trying to get around people who are considerably slower than me. It's one of the biggest complaints on running boards - people lining up without regards to where they should be in the pack, pace-wise. (And, as witnessed by the reaction of various boards when a man won it this year, any man who actually races it is due derision, of course.)
* If you want to argue that the female winner of, say, the WDW marathon does not get the same attention as the male winner, I can agree. But, in general, media reporting on marathons is somewhat worse than terrible, even when they deign to cover it, like Chicago or Boston.