So, the deleterious effects of trauma emotions “mattered less”. If you can never sleep through the night without waking up screaming, that is a bad effect. But if you only have a year or two of lifespan left, then you experience less “penalty” than if you had lots of years left.

Now, we ship boys off to war at 18, or even younger. They get PTSD in war, and then live 50+ years afterwards with the bad effects.

There are plenty of traits that provide us with no advantage, and some that never have.

Just because our bodies and our brains do something, doesn't mean it's useful.