Yes, but you've got the framing wrong: The issue is that employees who don't join the union are essentially "benefit freeloaders." The union employs people to negotiates wages and benefits and manage the union itself on behalf of all the employees, even those who aren't paying union dues. If everyone can opt out of paying for the union, then the union can't sustain itself.

Having a unionized workplace is a bit like having a democratic government – in the U.S., we're born and become citizens of the U.S. government and all that comes with that. We can't "opt out" unless we move out of the country and renounce our citizenship. We still have to pay taxes and we get all the benefits of our government (safety, education, roads, etc.) even if we don't want to – you can't just not pay taxes, right?

If you don't want to join a union workplace, just find a non-union workplace. If you don't want to join a new union, vote against it and find another job if they accept the union? That's more choice than you get with being a citizen of a country where you pay taxes! (And usually, union dues are less than the negotiated benefit/wage increases anyway.)