I don't think it's unreasonable, even though I am getting marked down for daring to ask, for people who are making assertions, even if they are well understood

I don't think it's unreasonable, even though I am getting marked down for daring to ask, for people who are making assertions, even if they are well understood *within their own community* (that is, not necessarily universally known) to show examples of what they are talking about. You're correcting someone, so it's clear that your understanding isn't universal, and example code is the absolute minimum.