They are, but corporations also have that right by extension of being made up of people. So the company, being a private entity, can say that you can't talk ab

They are, but corporations also have that right by extension of being made up of people. So the company, being a private entity, can say that you can't talk about the union while at work. It can show you "training videos" and other anti-union materials without repercussion. And it's mostly the union that wants it to be all or nothing, because that's the only way it really works. If 5 guys are in the union, but the other 95 are not, then the company doesn't really have to negotiate with the union. Collective bargaining only has power when it represents the entire collective. Or at least most. But if it is in such a position that it can start negotiating, I'm sure one of the things it will negotiate is that anyone working at the company must be a union member. Which is there, yes, to protect the union, but also the workers in the union. Because if the company can hire non-union members, it can slowly replace the entire workforce with non-union labor and eventually soft-terminate the union. The entire situation is complicated and there are lots of places where people can be taken advantage of from every angle.