“But now he/she is on a ‘mission’ to convince the rest of us that she/he is right, and we’re all wrong.”
Bingo! The agression tends to heighten when they feel cornered or threatened.
Yes and when he/she says “So we kind of agree on that point. Would you say?”. It’s not a really a question.
It’s a ‘I’m right and you’re wrong no matter what YOU say’.
I think in the medical world, they call that a PSYCHOSIS.