The problem is also that the power imbalance is severely stacked against the whistleblower. Sure, retaliation isn't allowed, but it's a far stretch to think it doesn't happen.

I've seen it happen, or what probably was retaliation, but how do I know for sure? They said the person wasn't competent or doing their job when they got fired. I don't know for sure if that was true, but I do know they reported significant theft that would likely have involved someone higher up, and not long afterwards he was fired.