Should anyone be forced to join a union against their will because everyone at their employer/in their role is forced to join a union?

In my view No, definitely not. Unions should be something people are free to join and free to leave at their own will. Especially since unions are often political in nature and not just serving their real purpose, and I generally oppose their political nature, I would not want to be forced to join one. This is one area I'm surprised where American laws are messed up IMO, in the UK under Thatcher the law was changed to ensure people had a choice - you're not forced to join one and can't be penalised by an employer for either choosing to join one, or not. In America it seems you can't hold certain jobs without joining that union and paying membership fees to it.