*Subjectively* Insufficient Cause?

This is may not have fallacies at all, but it's been bothering me for a bit. And yes, I really am that much of a sad bastard: sitting in the house all day, either touching myself or sleeping (and if I'm not sleeping, the only thing I'm probably thinking about is logically fallacious).

So...a person from X group is asked why they do something. They give an explanation, and it's dismissed because "other people in X group don't do that".

Example:

Neil: How come you had water instead of wine in your glass at the house party? You've never gotten lit before?

Brahim: I'm a Muslim, so I don't drink. It goes against my religious beliefs.

Todd: ...which doesn't make any sense. I've seen other Muslims that do drink, so that can't be the reason.

Todd says that Brahim being Muslim is not the reason he doesn't drink, because other Muslims do.

Another example is when someone tries to excuse the behaviour of someone.

Jessamine: Did you hear about the mass shooting in Ourtown?

Kat: Terrible tragedy. Apparently the man had schizophrenia or something; we need to improve mental health services in this country.

Patricia: What an insensitive comment. I have friends with schizophrenia and they don't behave like that. He's just a shitty person.

Kat: Don't you think it could have contributed in some way? Maybe feeling alone, or cornered, you know?

Patricia: It's disgusting to even consider such a thing. Those kind of attitudes dehumanise people with mental health issues. It's not a psychological problem; he's just evil.

Patricia rubbishes the idea that the Ourtown shooter was influenced by schizophrenia.

In the second example in particular, I think there's more room for discussion, because it's more complex cause-and-effect. Kat is guilty of causal reductionism if she argues/believes that schizophrenia was the only reason for the shooting, because it ignores social and environmental pressures as well. However, Patricia, in addition to being a little bit too emotionally invested in the issue, seems to just dismiss good probabilities out of hand because they're offensive.

What do "y'all" think?