Contradictions abound

when employers band together for the highest price possible it is outlawed as a form of reprehensible greed, while when employees band together seeking the highest price possible it is considered heroic and just

A union’s problem is painfully obvious: organized strikers must shut down the enterprise, close the market to everyone else—uncooperative workers, union members, disenchanted former strikers, and employers—in order to force wages and working conditions above free-market rates. If too many individuals defy the strikers…then unionists often resort to force. Unionists ultimately cannot impose noncompetitive wage rates…unless they can prevent employers from hiring consenting adults on terms that are mutually satisfactory. Unions must actively interfere with freedom of trade in labor markets in order to deliver on their promises.

More union mythbusting and government endorsement of the contradictions here.