Another facet of what I said above: facts don't matter. Emotions matter. Which is a stupid way to live, but that's humans.
The average person, if you told them like "the square root of 9 is 3, you fucking idiot" isn't going to believe you. Which, amusingly, shows they are kind of a fucking idiot.
That doesn't change the square root of 9, and it's stupid to discard facts because the speaker is rude.