Yes, I can see that. I was thinking mostly of my own context, where the vast majority of people know something of transgender-ness in the present sense, but I agree, "not knowing" is perfectly justifiable. "Not thinking of" is a completely different question, though, which indicates that someone does know something of trans issues, but pushes them to the margins and doesn't let them interfere with "easy" biological gender reductionism in the everyday realm.

To summarise, I'm thinking about distinguishing allies from the kinds of people who are considerate to one's face and then forget consideration when they leave the room.