Most native american populations are experiencing similar high suicide rates, and they don't all share this non-aggression ethos.
I think you're being optimistic. Parent doesn't mention any emotion besides aggression. No line was drawn between men shooting up schools and men not being able to cry, it was totally focused on aggression.
They point out that male-emasculation is leading to shootings, not repression of all emotions - I mean, isn't the expression of crying "emasculating"? I don't see anything but aggression in the parent comment.