Picard asked an interesting question in this movie: "How many people does it take before it becomes wrong?" So ask yourself that when thinking about this. 1 million people have to die where they wouldn't have before. 10 million people. 1 billion people. Why does the number matter?
And another question, why does killing one of the crew, say Data, more objectionable then if we kill 600 people?
What gave the Baku the right to ban the Sona from the planet? Was it wrong for the Baku to relocate the Sona? How many Sona had to die before it was wrong. Or is it OK because the Sona were ugly and the Baku leader was cute. Did Picard check who had the 'moral' right to the planet?
And the Sona weren't planning on killing the Baku- just moving them.
Come to thing of it Admiral Dougherty was probably the noblest one there. He wanted everyone in the Federation to share in the benefits of the planet while the Sona and Baku were thinking only of themselves (who can blame them). Picard maybe was guilty over what happened at "Journeys End" - although it was never said why he had such an about face .
This was addressed in the film. They could establish a separate colony. They "Don't want to live in the middle of the Briar Patch," remember?