alt Hacker NewsI think you're misremembering or misunderstanding Picard's argument. It isn't a tangent. Here's the transcript[0].
TL;DR Picard's initial arguments are pretty weak, even admitting that Riker as opposing counsel almost had him convinced. During a recess Picard talks to Guinan where she alludes to the future subjugation of many Datas which Picard connects to slavery. Back in the courtroom Picard calls Maddox as a hostile witness and gets him to define sentience--intelligence, self-awareness, consciousness--then walks him into conceding Data meets the first two. Picard's closing boils down to, "we don't know if he meets the third--you can call Data a toaster and rule he is property--_but what if you're wrong_". The judge rules on the basis of erroring on the side of caution due to that uncertainty. It's really a great scene.
We're not there yet, obviously. No LLM brings Data's level of awareness but it's as relevant a story as ever because it isn't really about AI but othering for the purpose of subjugation.