AI doesn't really care about disguise when using support power, iirc
If that's always been true, then the introduction of the Rad Attack specifically to target infantry seems to be the issue. It's one thing to have the AI use some dogs or terror drones to target your spies, which I do believe I've seen them do prior so I think you're right. But at least I can bring a few support units and kill those. The Rad Attack planes come swooping in from all angles and create a square mile of radiation. I obviously realize I'm in the minority, only playing AI, but this specific Support Power and Support Powers in general make this game less enjoyable for us. Oh well :/