I disagree. You speak up, then the PM gets defensive, it escalates, your boss steps in and tries to defuse but ultimately agrees with the PM. So now the choice

I disagree. You speak up, then the PM gets defensive, it escalates, your boss steps in and tries to defuse but ultimately agrees with the PM. So now the choice is to do what the PM decides or quit and join another company with the same set up... It's the man, man.