Men are not supposed to cry. It shows weakness (at least that's how it's perceived imo). Men are supposed to be pilliars of strength. Stoic, unrelenting, fearless. Look at the popular programming of how "respected" men are presented: Dirty Harry, Father Knows Best, John Wayne, "The Fonz" to name a few.
Moreover, these "stones of granite" are revered as sex symbols. There's a quote in the movie "Love Actually"...."no one's going to (have sex) with you if you cry all the time."
The images are hard to overcome.