I mean, the difference between "resist management giving themselves millions while cutting pay for workers" and "price fixing/restrict competition" is just an arbitrary, subjective distinction based on your opinion on how much money people should make. Either way the goal is to get more money for members of the group. If you don't think doctors deserve the inflated value the AMA has captured for them but think that other union workers deserve more money then that's fair enough but practically it's the same game.

There's also a word for what you're doing. A tautology I think? It seems disingenuous to classify unions based on "good" value capture. It creates a position where unions literally can do no wrong because they'll just stop meeting your definition of union.