this is not really true in all cases. there are things like ADD and other mental divergences which can cause this without neccesarily being based in trauma directly. there is research around it perhaps sometimes being passed down via generations (indirect trauma?) but this is not in all cases.

beyond trauma induced mental divergence i think good and bad are really a matter of perspective and opinion. people dont generalize well. we are all different. (except for that one guy...)

that being said, its sad either way and often doesnt end well.