Fine, let's talk broad and theoretically:
I hate to break it to you, but unions are a part of the free market. They're really not much different from any other company. Alcoa provides raw aluminum, Texas Instruments provides microcontrollers, unions provide labor.
Unions do not have a monopoly on labor. The types of labor they provide are available as non-union labor as well. Nobody is forced to use union labor, unless they've previously agreed to contracts which force them to use union labor. Nobody is forced to be in a union, everyone is free to choose who to work for, be it a union or non-union company.