Triggers don't pull themselves. People pull triggers.
Shooting into crowds isn't a rational act; ergo people who do so aren't rational.

https://www.nimh.nih.gov/health/statistics/mental-....

You state that the people who shoot innocent victims aren't rational, and support your assertion by citing a study that found 22.8% of people in the U.S. were diagnosed with some type of mental illness (covering all types, all degrees...including the most mild)in 2021. So you're equating not being rational with being mentally ill, and show that close to 25% of people in the US have a very mild, or more, mental illness diagnosis.

Although mentally ill people may have areas of irrational thought to one degree or another, thinking irrationally isn't synonomous with mental illness. Not at all. Many people think irrationally from time to time.

But I do agree with you that these shooters are not rational people. I disgree with your premise that it's the presence of irrational people that's the problem, and that it has nothing to do with the availability.....and I'll add adoration.....of guns in our society.