We all have our shortcomings & faults; no one is exempt from this.
When someone says something to you or asks you something, acknowledge it and answer that person.
It is better to say “I don’t know” or “I will find out” than to say nothing.
When you don’t say something, that person does feel ignored and don’t we all dislike that feeling.
Quite frankly, I personally think it is rude and not a good trait to have when someone doesn’t acknowledge and say something back.
I don’t think it is something we should have to tolerate.
We should all be willing to communicate openly and honestly and always be willing to learn more about being that way.