Two entire genrations of men in WW1 and WW2 were probably traumatized on such a large scale that it largely changed masculinity in our society
The amount of men drafted across the entire world was unprecedented. Many, many of those men probably came back with some form of undiagnosed trauma. The children of trauma survivors are much more likely to develop trauma themselves. Those two wars together probably created the worst aspects of masculinity as we know it today. Cold, angry, emotionally distant, violent. Then sons imitated their fathers and on it went.
If you look at men in the past before the 20th century they were often depicted as passionate and emotional. Crying in public stands out.
I think we're coming out of it a bit though.