You are making the same mistake as the post I replied to. You are "forced to join a union just because 51% of your co-workers signed" effectively everywhere in the US, not just in "right to work" states. If 51% of your co-workers agree, they will form a union, and that union will negotiate a contract on your behalf. You're in, baby.

"Right to work" only covers whether you can be made to pay union dues as part of this arrangement.

Partnership contracts bind non-signers from receiving benefits of a partnership. And with good reason: you wouldn't want any ole schmoe laying claim to the fruits of your labor.

Contracts deprive non-signers of things all the time. That's kind of the point.

Do you have a problem with corporations signing "exclusive" deals with other corporations?

I'm as far from a libertarian as I could be, but why should a libertarian think this? If you don't want to work for a company who has signed a contract with a labor union for a closed shop, you can go to a different company and negotiate your own. Surely I have the right as an individual to choose to join a closed shop, right?