Oh yea, even if this wasn't all true, it's still immoral to prevent adults from interacting however they want, be it gay sex or low wage work.
This is only true if there is true consent -- ie; a relative equality of power on both sides of the table. This is not the case currently at labor vs capital owner negotiations.
Again,
http://c4ss.org/content/4163(and that is a market anarchist site BTW)