[ConservingFreedom]

Most mass murderers are pot heads. Most Serial killers are also pot heads.

Possibly - but most pot users are not mass murderers nor serial killers.

[DiogenesLamp]

The fact that most Nazis didn't run the death camps doesn't make up for the fact that the ones running the death camps were Nazis.

The fact that most Muslims haven't gone on a murder spree, doesn't make up for the fact that the ones going on murder sprees are Muslims.

The fact that most queers haven't raped little boys does not make up for the fact that the ones raping little boys are queers.

The core of the problem is not what "Most" do, it's what a significant percentage of people who are given to those sicknesses do.