ThinkingThin, I think Ruth was just reiterating what you said. No reason to be upset.
I think the thing that confuses some people is that in the
Good Fats, Good Carbs Guide (GFGCG), it lists corn as "Very Limited" for Phases 2 and 3. I don't have the GFGCG in front of me, but I remember that in trying to figure out what the listings (i.e. limited, very limited, etc.) meant, we decided as a group that "very limited" probably meant "one serving, once a month."
Of course, you can play with this to see how you react. Corn is, as Cottage said, high in starch and sugar. So it can be very easy to have a reaction. Popcorn is high in fiber and you are likely to eat it more slowly, so maybe that's why it's okay in P2?