Maybe I should have started all this by saying I’m not an airport expert. I’m a dude who has flown on planes before.
I’ve always understood the terminal to be the waiting area that the plane pulls up too—in other words, the journey terminates at the terminal gate. Yes, I have only ever seen that area assessable after you’ve passed security—at least it’s been that way post 9/11.
If there is some nuance here where a terminal includes some parts outside of security, just say that. The tone I perceive in your post seems to be trying to make me look like a fool, and I don’t appreciate it.