Involuntarily binding the company to the contract would be bad, I agree.

But what's wrong with forcing the other employees to join to keep their jobs? That is fundamentally a requirement on the company, that they only hire people in the union. And that's no different from any other sort of exclusive contract. If a restaurant has an exclusive contract with Coke, is it sinister to say that Pepsi employees can't supply them, and they have to join Coke if they want to do that?

I'm saying suppose some employees decide to form a union. And the company doesn't consent to sign an exclusive contract. As I understand it there are unions advocating that workers that didn't agree to a union still have to be bound to it anyway.

It's my understanding in some states in the US it's possible a worker will be forced to join a union if a certain number of other workers want a union, even if neither the worker nor the company hiring them consent to it. In about half of states under "right to work" though they do give employees the option to not join the union if they don't want to.

This happened to me when I was working a ~minimum wage job at a grocery store. At the time it was not a right to work state, and I was forced to join the UFCW. The union I was forced to join then made me pay dues, pushing me below minimum wage.