Anti-trust arguably is. Child labor arguably is. But executive compensation is not. That should be a matter for shareholders. But if no one acts, that still doesn't make it right, or a proper public example. If the shareholders cannot act, or are prevented by clever rule from doing so, it falls to those of position to act, as they did in the past. And remember that past, again, of robber barons, corrupt police depts, city halls, and nepotism up and down the line of government service. It took an unofficial hand to keep 'up appearances'. That seems to be lacking today.
Shareholders act all the time. However, the shareholders aren't typically the widows and guys trading a hundred shares at a time on eTrade, they are the mutual fund guys and the big unions who control billions. And when they whisper to a board, the board pays attention. And in the larger scheme of things $50 million isn't a lot of money.
As for Robber Barons, they "built stuff." They weren't nice guys -- in fact, they were brutal -- but they built railroads and steel mills. Eventually, they out lived their usefulness and faded from the scene. A good percentage of the homes they built in Newport are now museums, a fact that is indicative or something or other.
Get off your implied moral high-horse and out of that Ivory Tower of your mind.