I understand that the Federation doesn't govern the Baku. You're stuck on my use of eminent domain, but that was merely an analogy.
And no, it is not "simply unethical," as there are many, many folks out there who agree with me, and there are many ethical systems which would view removing the Baku as the right thing to do.(indeed, probably most would)
Brent Spiner himself criticized the film's ethical viewpoint, as did Roger Ebert in his review of the film. I think the story's bad dilemma is part of the reason the film wasn't very popular.
There is no dilemma, just an incredibly simple morality tale like The Drumhead which obviously had to be told if so many people do not understand the constitutions of their countries. I don't care how many folks agree with you and I don't care how direly you have to appeal to majority in order to be able to sell theft, kidnapping and murder.
You advocate that a stronger nation steals an asset from a weaker one and crushes its population in the process instead of politely asking for trade and negotiating for a price.
You can rationalize it all you want via pretending that the stronger nation cares about the common good, imperialism remains imperialism.
By your logic Romulans, Klingons and Feds would have had the right to raid and rape Ba'ku because their empires are large, because trillions of people could gain from the radiation, because they all care about the common good. Bullshit, they merely care about themselves.
I hope you never stand on my door, rush in, trample me down, take something from me and tell me while going out that you value this particular asset more than I do ... and in addition to that you have the audacity to claim that your act were ethical instead of admitting that you are just a petty thief.