There are many who have experienced trauma and or traumatic experiences.
There is a theory somewhere about the number of people who know someone, who then know somebody etc, maybe even eventually someone famous. Anyways, if one person directly affected by P.T.S.D. issues knows several people, who then know several others. Would it not make sense they are somehow indirectly affected by the ongoing issues?
Traumatic experiences vary in the way they are perceived, by those experiencing the after effects — as well as those who are indirectly affected.
In a fuzzy logic way, it may even be a majority are somewhat affected by ongoing issues related to potential stress from those afflicted directly.
Emotional release is a key to a balanced healthy atmosphere. There are so many ways to release the tension and stress. A lot are even little or no cost in economic sense, but the future rewards are perhaps worth it.