1. It's problematic. Why are we assuming that an old woman can't also be a badass programmer? Plenty of CS luminaries (a) were women, and (b) had kids (c) who themselves had kids, and therefore are someone's grandmother.
2. Your audience isn't necessarily non-technical. Generally your audience is going to be someone who's qualified to take the course. Which means that a good explainer is going to, as you said, have a high degree of empathy to beginners... but not explain things at such an introductory level as to leave people bored.
3. I don't agree that people who can't explain things well to non-technical people don't know their stuff; they lack an important skill that could make their knowledge far more useful to humanity, but that's a different claim from saying that the knowledge doesn't exist.