Or actually the actions that stem from their interests also end up benefiting you as a side-effect. Say going public with the story. Well now they are forced to protect the PR image so they will actually do something to fix the problem (move the manager to a different location), give you more money to keep quiet, etc. But they are not doing this for your they are doing it for the company's sake.
(Your value + cost of incident - squeaky wheel cost) vs (manager's value)
The incident has to be fairly egregious to tip the scales in your favor, and the squeaky wheel cost can follow you.
But you are right, it is the nuclear option. After that even if problem is solved immediately, a stab in the back in the future is expected.
As for future employability, you are right as well. However, I can see a small start-up actually seeking out self-reliant people who have a sense of justice doing what is right. So the quality could also be appealing.
Sure, but that doesn't mean that they can't be on your side. If you report that your boss is doing something which is against company policy and hurts the company, it's quite possible for HR to be simultaneously on your side and on the company's side.