They don't believe in technology.
Yet they were able to accurately determine the exact problem with Data's positronic brain. They might not use it in their daily lives, but the Baku did possess technology.
Yes they were, and this is why. After they found out about the beneficial properties of the planet, they then did not
use their starship (starships) to spread the word to other species that could have benefited. They kept the knowledge to themselves.
And that is the Baku being selfish.
It's dying--condemning 600 people to die--that would ordinarily be immortal.
There is no reason to believe that the Baku wouldn't have the same access to the radiation from the collected particles as others would, the main difference would be the Baku would no longer have exclusive
Picard asked an interesting question in this movie: "How many people does it take before it becomes wrong?"
I would have loved for the Admiral to have immediately confronted Picard with the opposing quesion of how many people have to be helped before it becomes right?
Picard didn't have a logical leg to stand on.