It's not a double standard, it's one standard for a corporation and a different standard for a labor union, because those are different types of organizations.

When companies do that, it's waved away with "it's their right". Just look at stuff like the iOS App Store, Microsoft Antitrust case, etc.

When was the last time there were any actual consequences for the actions of a large corporation?

Companies throw their weight around constantly. Workers shouldn't be able to as well?