It can protect your career when you are being asked to do something that might be illegal. Especially if you have a security clearance of some sort and it would violate it.
This might be an important distinction between ethical and moral. Standing up against unethical behavior protects one career, but if the behavior is ethical but immoral (that is to say, it violates your own standards but is deemed acceptable in the larger community) then it doesn't really protect one's career. But the self image protection might still be worth it.
...by force. Although I’m sure Edward Snowden feels good ethically, I’m also sure he has material issues that make him regret (that’s the goal of his ennemies, after all).
Similarly, a middle manager who has to downsize houses because he stopped working on weapons for example, it could be even harder for him because he won’t even get famous for it.
I should know, I’ve made one of those choices in another area.
That's assuming that your input affects the current situation.
Sure, if you leave the company and go somewhere else, then you're potentially going to find your moral environment. But, there are better ways to find these environments, versus job hopping.
Without leaving, how often will your conflicts affect your situation?
Would like to hear more about the predicted benefits.
That's a question for whoever's standing up - how do they measure career success?
Going by the theme of the post, "By making as much money as possible", wouldn't be an unreasonable measure.
If you truly value a moral career, there are surely better ways to find one than to join a company and express your opinions internally, in an almost retroactive manner.
This might be an important distinction between ethical and moral. Standing up against unethical behavior protects one career, but if the behavior is ethical but immoral (that is to say, it violates your own standards but is deemed acceptable in the larger community) then it doesn't really protect one's career. But the self image protection might still be worth it.