The data simply do not comport with the position you are advocating. Here's some old (2005) data: https://www.bjs.gov/index.cfm?ty=pbdetail&iid=653
- 20% of people in US had contact with police in the year. - 9/10 people reported police acted properly - 44 million people with interactions, only 1% of those had violent conflict involved with the interaction, that's 440 thousand incidents
Hell, even the left-leaning WaPo tried to use data to buttress their/your argument and it's just plain embarrassing: https://www.washingtonpost.com/graphics/investigations/polic...
- 1000 people shot by police in 2019 - they actually removed the numbers for unarmed, because it was so dismal for their message - less than 50 "unarmed" black people killed by police in 2019
Take an honest look at these numbers and then please try again to justify your position about how there's a "high chance that the individual will end up shot by the police" because by the light of the data you're living in a fantasy land.
But then my next question is, what does a police officer bring to the table other than a gun? What unique skill and tools does a police officer have that could help resolve such a scenario peacefully, that wouldn't also be available to someone specially trained in dealing with mental health issues?
We know from plenty of examples that in the scenario you describe there’s a high chance that the individual will end up shot by the police, and probably dead. We know police don’t have the training or the tools to handle this scenario well.
I don’t see how brining in people with better training could be a detriment. Worse case you ended up back where you started, the “violent and irrational” person ends up dead. Best case they successfully deescalate and render appropriate treatment, saving their life.
Not sure where the downside is.