Unions are just businesses that sell labor. There’s nothing wrong with getting a bunch of people to cooperate on selling labor, any more than there is with getting a bunch of people together to cooperate on selling bananas.
Unions are rent-seeking behavior and that’s the problem. Voluntary unions are one thing, but the way unions are build today is requiring labor to participate and for businesses to buy from the union.
Rent-seeking behavior of any kind holds humanity back.
