“...for the purpose of shaking down an employer for things they could not gain through merit.”
Employers take advantage of employees plenty of the time. As for the usual, “so start your own business”, not everyone can own a business.
There are good union employees, there are crappy union employees, and everywhere in between. Just like non union.
See Commonwealth v Hunt
“Employers take advantage of employees plenty of the time.”
So? They OWN the business and employees are not slaves. They can quit at any point. Not happy? Then leave the company. Don’t organize a mob to shake down the person who created your job.