Most of these mass murderers wouldn't have been flagged as insane and dangerous back when we had accessible long term mental health facilities for people who are dangers to themselves or others.
There are criteria that were sort of even necessary back in the last era of long term psych hospitals (70's-80's) which is they have to demonstrate they were a danger, (or in the old days, have really good insurance or rich parents and any diagnosis that could keep them in until the funds were exhausted).
Criteria exists to prevent abuses of people who aren't ill enough to be involuntarily committed.
Yes it has made it harder to commit people but that's not necessarily always a bad thing. Because again, many of these murderers wouldn't even be flagged. Many hadn't been diagnosed with anything. Many don't have friends or family who have more than slight concern. Most are surrounded by people who couldn't conceive of them doing something like this, even if they exhibit odd behavior or obsessions with violence and hate.
Of course lack of access to mental health care and long term facilities for people with issues is part of our nation's health crisis but again, even if we had accessible care for mentally ill people i don't think it would make a difference for a lot of these mass murderers. Most of them aren't cases of cycling involuntary holds and desperate attempts to get them treated or housed while they're seriously ill, and necessitating stablization, like Andrea Yates.
Most of these people quietly simmer under the radar until they erupt. Oh there are signs but usually not anywhere close to enough to act even if we had excellent health care for people with mental health issues.
