This is another top-notch season 3 episode, but the core inconsistencies with The Measure of a Man are pretty glaring. Try watching them back-to-back, it's confusing. We see Picard on both sides of the argument in the same episode. First he calls it an invention, and then he tries to prevent a child from being separated from the parent.
Actually, I think the inconsistency adds to the authenticity of the story. Picard has got high noble ideals, but like, I think, most of us when given a surprising new situation he wants to keep things as close to the status quo as possible. Given a bit of time his reason and the better angels of his nature that reason creates shine through, but, he can still be caught by surprise and in ways that aren't always creditable.
Too much of this and you'd get a sloppy character, but I think the reflexive reaction of Picard here is just enough mud on the boots that keeps him more real.
(It also serves the plot role of foreshadowing Admiral Jerkface's involvement and the change of heart that for Picard comes easier than for Jerkface.)