I will state this once as simply as I can: stock market investors are rewarded for funding companies by taking on that risk in hopes that the companies they invest in produce a profit. It is overwhelmingly similar to the process you are describing with your credit union, but in a much more distributed way.
> Workers don’t need the shareholders, and they get nothing in return (except lower salaries).
There would be no workers if companies didn’t have the capital the needed. So no, the workers very very much need the shareholders. The money has to come from somewhere. No bank is going to bankroll the next Airbnb, Uber, Instacart, DoorDash, etc.
Beyond that, the workers aren’t owed a penny more than they agreed to be paid. If public shareholders didn’t exist, the owners would have full ownership which is what happens with small businesses. Nowhere in these circumstances are workers any better off. Profits and losses are not their domain.
I’m sorry if I sound like I’m talking down to you. It is just that you are a victim of cognitive dissonance possibly due to your unconscious bias against wealth.