Of those, I recognize police as relevant to the topic; taxpayers shouldn't be footing any money for the employment of anyone else you mentioned, and a responsible state which respected our human rights would not.
So as a thought experiment, do you think society is generally more or less safe having a well educated, healthy and mentally sound population at large?
Let me put it more simply; do you think a society comprised of
desperate individuals is more or less likely to be safe and in good order?
If you can envisage that a healthy society is comprised of healthy citizens, then it logically follows that those services are not in fact irrelevant to crime, and that if those aspects benefit society as a whole, it also benefits society to have those services exist at a decent quality by paying to ensure that.
If I understand you correctly, you're saying cops are cops for benevolent reasons and don't care so much about being paid, so they need a union to argue for them so they get paid better.
I'm saying that earning money is not a primary motivator for people who go into those kinds of jobs; they have alternate motivations.
Some of those motivations are benevolent to society (wishing to see a crime free and ordered society).
Others are not (wishing to exert power over others).
Their wage on the other hand is still a matter of them agreeing to work for an employer at a rate they and the employer agree upon. We are the employer.
Explain to me again why you want a middleman so you can't hire or promote or increase pay based upon merit, fire or demote or decrease pay directly on merit, but instead want seniority-based hierarchies and this secondary organization with its own distinct political influence and agenda between you and your employees? If you really want to pay them more, whatever your motives, it's simple, you get enough other people to agree with you and you vote for more funds for police wages.
Why have managers in the private sector at all then?
It's the shareholders who pay peoples wages, so the shareholders should be free to dictate the terms under which employees work, and they can just leave if they don't like it.
Because the relationship between tax-payer and public sector worker is just as abstracted as that between a stock trader and a private employee.