I don't understand the argument in this response: unions exist within capitalist systems, and are an integral part of
our capitalist system. Our concept of a "union" does not apply to non-capitalist systems. Extolling the virtues of capitalism is, at the absolute best, completely orthogonal to the legitimacy and value of unionization.
Likewise, unions aren't "politically created structure": they're not created in a top-down manner by the state. They're a form of collective organization and bargaining, the sort that is singularly responsible for the quality of life and workplace protections that we all take for granted.