There are things that are true

Sure. But there is no objective arbitter of truth.

In a similar vein, if I'm standing at a train station discussing some topic with a friend on which we have different opinions w.r.t facts, I would not feel comfortable if a stranger would come up, insert themselves into our conversation and start unasked to "correct" one of us (or both). Occasionally and if it's done very politely, maybe. But if that happened every time I'd be seriously annoyed. Correct or not.