I would stare at him and ask if he knows what a passing tone is. But it he's really pointing out my actual mistakes, I'd tell him I know because I was also in the room and nobody needs to hold my hand.
Then I'd go home and think about whether I want to continue playing with people who can't mind their own business.
But my experience is that people, even good players,
don't always know if they've got it wrong, especially when the music is complex, tricky, or unfamiliar. We're not perfect, and we don't always recognize our mistakes. I'm not averse to someone letting me know that I made a mistake. If I'm in an ensemble, what I play isn't solely my business. It mostly is, but we are--or are supposed to be--all in this together.
If I did in fact get it wrong, and the correction is offered in the spirit of helping us all get this piece of music better (rather than just an attempted putdown), then I acknowledge it, say thanks, incorporate the correction, and move on without rancor. I would expect the same of bandmates.
Sure, we'd all rather catch and fix our own errors, and would like to assume that we always can, but if we don't, it's not a dealbreaker if someone lets us know in some basically considerate fashion. That's not necessarily a failure to mind your own business; ideally, it's part of a group effort to get things right and make them better.
Admittedly, here I'm not talking about the odd mistake here once in a while, because everybody makes those; I'm talking about things that are consistently wrong. I'm not recommending jumping on someone for every single (perceived) missed note.
Of course, the real annoyance is when we're not wrong, and somebody else is trying to tell us we are, out of ignorance or competitiveness or gamesmanship or whatever. In those case cases I'll argue my position as stubbornly as anyone.
