There are a lot of people, including me, who know from personal experience that unions employ terrorist thugs as one of their primary tactics for holding power. I celebrate with each decline in union membership and with each union that is decertified.
Years ago, a buddy of mine worked at a small company making castings. He had to join the union or he couldn't get a job. After a while, he and the other workers saw no benefit of them paying dues, so they stopped. A few days later a Suit and two goons show up. The goons say that if dues weren't paid up, there would be some "accidents".
At that point, my buddy and his pals all took up the sledges used to open the moulds and said that the "accidents" wouldn't all be to them. The Suit steps in with the "Now, now fellas . . ." routine and promises that they would see some changes. Everything calmed down and they all left.
The workers foolishly started paying their dues again, and of course nothing changed. My buddy left soon after.
In the 50s and 60s I was forced to work in two unions - garment workers at Macy's in NYC while I was going to trade school, and the Typographers Union in San Diego. I never saw any violence or threats - just the flat out attitude of "Shut up and pay your dues". I went to the Typographers one time about a boss who thought it was still the 1930s and treated his workers accordingly. All they told me was "Well, Ole Walt is just a big bear. You'll have to put up with him." Luckily I heard about computer programming . . .
There was a construction site on the road I take to get to work. There were building a parking structure for a mall. The steel workers would park their cars in a lot across the busy street (Victory Blvd & Canoga with Topanga Blvd on the other end in the San Fernando valley) and instead of using the crosswalks they would stride en mass across the road bringing hundreds of cars to a standstill. They did this day after day until the the job was done.
Naturally no police anywhere near the site to enforce you know the law!