Another example of how unions are absolutely a part of the free market.
A bunch of small sprocket companies are selling their sprockets to Mr. Spacely for $1 each. They get together, and agree, they will not sell him any sprockets, unless he agrees to buy them for $2.
Mr. Spacely has a problem, he needs his company to keep running, but he doesn't want to pay double.
He can either curse the sky, run around, get red in the face, and huff and puff about how he wishes he could FORCE them (with price fixing laws, perhaps, yes, those are force, not free market!) to sell them to him for $1 a piece, or he can try to negotiate with them. With any luck, he may be able to get them for $1.50 each.
Now, how much are the sprockets worth? Any free market geniuses here know?
Answer... ...the price agreed upon, not what Mr. Spacely says it should be, and not what the sprocket companies say it should be. This is not a new concept. 1776, Adam Smith.
Now that we have covered elementary economics, change "sprocket companies" to "workers" and "sprockets" to "hourly labor".
Uh oh... ....now what? Your "unions are not free market economics" argument is revealed for the sham it is.