Men in this society are valued for capability, reliability and durability. Anything that threatens their productivity, or could render them a liability rather than an asset in any given situation... makes them widely considered to be worthless. It sucks absolute donkey balls, it's profoundly destructive, and it shouldn't be this way, but it is. And on top of that, guys get told they're not being intimate enough if they don't 'open up', so they have to carefully craft a second mask, over the top of the first one, simulating just a little tiny but of emotional leakage, but not enough to threaten their perceived usefulness. Of course they dare not let anything real slip out; for one thing they get no opportunity to practice a controlled release at any point in their lives, and for a second the sheer quantity of shit they're holding back will destroy the entire dam if they poke a little hole in it.