I agree with you, but I have to point out, because it's so common: The "this will be unpopular, but I don't care" preface is, I feel, about as damaging to the perception of whatever you're about to say as "I'm not racist, but". To make an effective point, I think you should avoid, as the first thing you say, painting yourself as an underdog brave enough to speak out by preemptively criticising your audience's reactions that haven't even happened yet. That's not to say you should never admit those observations - rather, I would reserve such broad criticism of people's opinions for a separate train of thought or conversation.