Comment: Unions are Monopolies on Labor

"Just as being for unions doesn't make you a socialist."

Yes it does, or rather it makes for Central Planning (aka Socialism, Marxism, State Capitalism, Serfdom). Unions are Monopolies (Monopolies are Centrally Planned) over a labor market.

"In a free market unions exist."

No they don't. Free Markets (aka Capitalism in its original meaning/context) abhor monopolies. Unions are Monopoles on a labor market. They limit Competition which is necessary in a Free market.

Not to be a stickler, but Unions are nothing less than a Trust, Monopoly, or Cartel if you prefer over a Labor Market. Monopolizing Capital, Resources, and/or Labor creates a centrally planned (unfree) market.