That trial wasn't about Picard recognizing data's sentience but about the unresolved question of official legal recognition of his rights and status. It's also shit I would think had come up when he tried to join star fleet. I mean, what did star fleet regard him as before that trial? A walking computer with a military rank and command authority but isn't a person?
The real problem you seem to be getting at is the divide between AI's in star trek, and holographic programs, that are some how not considered AI's. Consider how in voyager star fleet uses their EMH's as slave labour in mines and how in Picard, even after having banned all research and use of AI's for a decade or more, they still use emergency holograms with near human intelligence without pause. The only explanation would be that holographic intelligence's and AI's are somehow not the same thing in Star Trek.