Unfortunately, I tend to feel the way you’ve described quite often. Sometimes, I’m even made to feel arrogant for feeling that a speaker or teacher is being condescending. I’d much rather be made to feel stupid for having to do homework later to unpack what someone had to say. I think I realize that more often, a speaker or writer is simply trying to lengthen his delivery by including bits that everyone already knows. We do have minimum lengths after all. We don’t want our article to sound like a blog post, nor our sermon to sound like a homily.
Indeed, I believe we can exhibit humility and express respect while speaking of our desire for change. Respect is not only shown in assuming that people already possess a specific bit of knowledge, but also in the assumption that they have the ability to garner the bit that they currently lack.