re: Mental Illness related to mass shootings seems to be overblown

1) You're confusing a serial killer, who gets victims one at a time usually, vs a mass shooter, who usually gets multiple victims at a time.

2) Mass shootings include anything from drive-bys to schools depending on if it meets the required amount of potential victims. So yes there are a lot of nonmentally diseased criminals over and above the number of mentally diseased criminals.