Lol, my father constantly telling me to toughen up is what led to me going to therapy.
Toughening doesn't permanently do the trick, it leads to repression of emotion and is a very isolating thing. It's better instead to be vulnerable and expand your support network. One strong tree isn't as strong as the interlocked roots of a forest.
Like most things, toughening up can be helpful in some situations but when used for everything it becomes counterproductive. Like letting petty insults slide when they don't matter is a pretty handy skill, but there is a need to also know when not to and when to reach out so that there is support for when it is needed.
I'll bet more than one of them had serious mental health issues that were exacerbated by being told to just 'toughen up a little bit' when they reached out for support. Calling people cowards for acknowledging issues promotes a toxic view of men being able to open up about issues.