Masculinity

I dont understand why there's so many different opinions about masculinity. Men can wear nail polish or cry, they can express emotion or act childish when Happy? I don't understand why or when these rules where made. 

My biggest issue with masculinity was how it was connected to a body count. It either be one related to sex or one related to violence. It was weird how people would call men, unmaly or gay if they didn't speak about or always do things like this. This and that men couldn't be private. When men wanted to be private about their life, they'd be called Lone wolfs or some other emo stuff. Most men pee in public, talk about their affairs loudly and are open about private things. Unless it comes to something they deem unmanly, such as feelings.

On the other hand, I understand why men act like this half the Time. Its  a preference that women have, for a man to be open and easy to read. But emotions were to girly, too much. And women didn't want that. Also, other men would judge you for being different and relationships are already hard as a man. 

It's truly hard to find what masculinity is as everyone has different views on the topic.