"You're a bad person if you disagree with me" is a great way to never get what you want. It's not simply stating your position, it's anti-persuasion whether you want it to be or not.
Saying “you’re a bad person if you disagree with me” draws a line in the sand that precludes civil disagreement and picks a fight. Most people like to avoid conflict, and any possible counterargument to “you’re a bad person” inevitably comes across as defensive.
In other words, the tactic is to bully the opposition into shutting up. And it works very well.
