Ah, yes, the big, bad UNION .
Yes, them. Labor unions are nothing but monopolies (or wanna-be monopolies), whose sole official purpose is maintaining and increasing the prices, their members can charge. As such, they ought to be treated to the anti-monopoly laws as well as, when the members break the law (for the union's sake) with the federal RICO law — as racketeer-influenced and corrupt organizations — rather than have each beating, shooting, or property destruction treated as isolated crimes committed by individual members on their own.
On top of it, any union, whose connection to the bona-fide crime is proven (even if it is just a single union official), must be disbanded automatically and immediately — the innocent members, who wish to unionize again, can do so under a new name later.
Both are doing it for profit for the companies and directly against the interest of their own employees.
They do. But they've grown to become that way naturally — not by using the law to force others to join them, as the unions are legally empowered to do.
What about the collusion among tech companies to not hire each other's employees?
Such collusions — if they are legal to begin with — are not supported by the existing law. Very much unlike the unionization — whereby a group of employees may vote to "unionize" a particular workplace and then they get to force other employees to join their union as well as prevent the employer from hiring outside of the union.
Sure, people ought to be free to associate with each other. But labor unions have much more law on their side, than a church club or a bowling league. And that just should not be the case...