They’re secretly gay and are afraid that seeing feminine concepts and objects will make them slip up and do something fabulous, so they put their emotions in a box and CRUSH IT

To be fair, it’s only a very particular subset of grown men. For instance, I am a grown man, and I have no problem with Barbie stuff. In fact, I’m gonna go see the movie next week because I’ve heard it’s incredibly good. Weird reactions to stuff like this seems to always come from men who are members of hyperconservative and often theologically-oriented groups.