Perhaps I should have said, "Can't hurt you much." But the AI never uses that garrison for anything but sniping, in my experience so far. A human opponent could be more creative, I'm sure.
As your air power experience shows, it's hard to knock out the troops around the nuke facility--especially that little outpost down south at the T-junction! Those must be the elite do-or-die Presidential Guards Martyrdom Battalion. Sometimes, letting the jets draw fire from AA units and then hitting those units with Cobras works.