Edit: to clarify, letting the employees of a public corporation decide the direction/priorities would be like if the employees of a non-profit had a union which could force the non-profit to change from planting trees to something unrelated like washing dogs. The people who donated money would probably be upset that they were deceived about what the donation would be used to accomplish.
Who's forcing anyone? If the company doesn't want to play ball they are free to hire replacements when the workers strike. If the workers don't care enough to risk their jobs over it then their bluff has been called.
If the company does play ball and the shareholders don't like it they are free to elect a new board or sell their shares.
Yes, this is where negotiation between owners & the union comes in. Sometimes reality can disagree with a decision shareholders voted on and that is okay.
Money is not the only value here, so I don’t see why it has precedence over what other’s find valuable?
I don't agree with that assessment. If Google employees have a strong opposition to working with, say, federal agencies to share data they've gathered on users, then I think it makes perfect sense for them bring that concern to the table.
Honestly, I don't see why a union shouldn't have the ability to bargain anything it wants to try and bargain. I'm open to someone changing my mind on that.