Those of us that talk about things like mental health are not doing it to "make excuses" or whatever strawmen are flying around at the time.
Those are the people that see the nuance to problems on the societal level and then attempt to figure out ways to fix or alleviate those problems. When talking about mental health, it's talking about restoring the infrastructure that was removed in the 80s in America to help those with problems, and also to remove the stigma that centers around mental health so that problems that lead to things like this can be addressed before they turn into things like this, more often.
"Pointing blame" or simply labeling people as "evil" or whatever only serves to make the person who says those things feel better about life and play into just-world fallacy. It's easier to just say "some people are evil" than to think that friends/family/neighbors are just a bad day or a further shift in chemicals from doing something horrible. Thats also why people would rather focus on criminal punishment than the society that leads people to being criminals, clear black and white lines of "good" and "bad" just make the world less scary to them.