> If you see something stupid, call it out. If I’m doing something stupid or say something wrong, call me out!

...but that can be done politely, or not(†). In my experience, being polite doesn't add a high cost to calling someone out, makes the person being called out less upset on average, and generally improves the quality of ensuing answers/discourse (because those involved aren't burning emotional energy on pushing their anger to the background). Both of those latter two things are good.

Sure, there are some people who can take a flaming load of unfiltered criticism to the face and remain unfazed, but assuming that that's the _norm_ doesn't seem especially realistic.

(† = Or in between - "polite" is not a boolean. It's not even a numeric measurement; one can be polite/rude in different sorts of ways.)