How do you know they've done it?

Do you have to leave them in front of kids teaching students until they're convicted?

What if that takes months? Or never actually happens? But the teacher has crossed the line inappropriately enough times that no parent wants their kid in the same room with him?

In the most positive light, a union might protect a genuinely good teacher being unfairly accused or targeted for political reasons from being put out of work. But sometimes following the processes for ensuring that can be so unreasonable to work through on a practical level that it's easier to just keep them employed but away from students until it gets resolved or they quit.

There's a famous PDF that gets shared when this comes up (although it's geared toward an incompetent teacher):

https://reason.com/wp-content/uploads/assets/db/126393089187...

US teacher salaries are abysmal. When education funding gets cut the school boards the unions successfully negotiate stronger employment protections (after all, if a job pays poorly you need to attract employees some other way, such as good PTO, benefits, or in this case: a job for life).

It’s also entirely possible that even without the unions, the school boards don’t want to get rid of bad teachers simply because they’re already, and chronically, understaffed.

US teacher salaries aren't nearly so bad as you're thinking. Median is around $60k, which compares favorably to the median household income of $59k - and teachers get better benefits, too.

Yes, it's not tech-level pay. But it's not exactly "abysmal" either.

Teacher salary is dependent on how wealthy the school district's tax constituents are, because education funding in the US comes from property taxes.

Given the amount of education, time and their own resources they're expected to put in to do their jobs, I wouldn't categorize them as "good", and would say generalizing their compensation as poor would be accurate given those points.

I’m not sure where that number comes from, but I know in my fairly high wealth state the maximum amount a teacher’s salary can be is about 45k. Benefits are about the average for that level of employment, nothing I’d call “better” than anything else. My ex is a teacher, and I make well over three times her salary. We both have Master’s degrees - that’s also required to be a teacher.