The whole concept of collective bargaining kinda evaporates when the collective is small enough, and the company large enough, that the company is be able to not give a duck about the entire collective and their collective actions. In this case they can just fire them all on the spot ("can" as in are able to, not as in have a legal right to) and it evidently doesn't cause any large enough issues for them.

I sympathize with the workers, but they clearly overplayed their hand.