The two main reasons I hear are being afraid of being seen as weak, and having those displays being used against you later. IMO both are kind of BS… Mike Tyson cries a lot and I dont think anyone sees him as weak. And if you know somebody will use any moment of perceived weakness against you later, why the FUCK are you keeping them in your life lol. As the kids say…. "thats an OPP"
I think we are getting better about this but I still feel like men in general have a long way to go in terms of emotional honesty and maturity.