Are you suggesting that if the Federation had simply asked the Baku to share the particles that the Baku would have happily packed up and left the planet?
I find it more likely given what we see that they would have said, "Sorry for your problems, but they're none of our business." Which, ironically, is exactly what the Feds would have been in a position to say to the Baku when the Son'a came knocking.
The whole idea that whether you should be willing to make a small sacrifice to benefit even hundreds of other people should be contingent on whether you were asked nicely first is ridiculous. It no doubt becomes obvious to the Baku at some point during the film (if not decades earlier) that they're sitting on the Cure for Cancer, but instead of showing any willingness to share what they have for the benefit of many, many others? They sit on it. And they don't even have the courage of their convictions, because it's not like they actually refuse to see violence committed in their names...they just don't want to pull the triggers themselves. Yeah, that's noble.
How exactly is this -not- selfish?
Yes, I'd get pissy if I came home one day to find I'd been evicted. But I'd like to think I could look past my pride if I found that not only had I been evicted because my home contained the cure for AIDS, but I was being given a new home, free of charge, that was at least as nice as the one I'd been evicted from.
But hey, if you want to sit on a medical miracle until someone specifically asks how much you're willing to sell your house for, that's your business.
Good people don't wait to be asked for their help; good people offer their help.