Dues deduct from your paycheck

So does every other subscription "service.", but we don't talk about the vileness of a Netflix subscription do we?

No guarantees on pay, benefits, or work rules

This is just a lie. I cannot find another angle to it.

Even without a union, there is no guarantees on pay, benefits, or work rules. So the point is moot. It's like saying "Anything is possible" and walking away like you said something sagely.

Typically must go through union instead of your supervisor or manager

Most people wouldn't understand why this matters unless you've been apart of a job where your manager has defended you against your supervisors. Very few people have had this happen, but the idea is that you will have people that DEFEND YOU from your supervisors getting power hungry.

It's not even like your supervisor can't bring accusations against you, it just means that complaints would have to have merit.