I assume that everyone who signed on to this letter understood the likely consequences and accepted them — because they understood their firing would massively

I assume that everyone who signed on to this letter understood the likely consequences and accepted them — because they understood their firing would massively amplify any workplace concerns by turning it into national news and making SpaceX employees mistrustful of management. This is the problem with being predictably retributive: once everyone understands how you work, your behavior can be exploited.