> Imo, the kind thing is not to denigrate anyone, including people that can not possibly be useful.

Exactly.

In fact, I have always found it advantageous to treat people "far down the ladder" with respect and kindness.

This has always worked out well for me. These people know everything.

Interestingly, I've especially struggled with this with those in closest with. It can be hard to "turn off" your friendship and be more respectful with someone you are comfortable with. But when you're in a meeting with other folks, a joke that might come off as friendly (giving someone a hard time) is suddenly misinterpreted by others.