Like I've said a hundred times before in these threads, the Federation's actions likely prevented the Ba'ku from being exterminated.
So your saying Picard did a good thing seeing as the Son'a were planing to do that near the end of the film.
Of course he did a good thing. But you're saying he did a bad thing because you said it should be between the S'ona and the Ba'ku. By your application of property rights the Federation had no business to be there. The Ba'ku never asked for Federation intervention, one way or the other.
However, Picard should've never been there to begin with. He should've followed the orders he was given by Starfleet and Dougherty to go to the Goran system before he knew anything was going on in the Briar Patch.