Having to point out that violating the sovereignty of another nation, kidnapping its citizens and stealing their resources is imperialism feels like having to point out that forcing somebody against his will to do something sexual is rape or that simulating drowning is torture. It shouldn't be necessary to have these kind of pseudo-discussions in a civilized society.
By the way, I am totally for the Cardassian land for peace treaty (the Feds once abandoned cloaking technolgoy for peace). The Maquis are Federation citizens and subject to the laws and treaties of their government. If they don't wanna leave the dangerous border region they gotta live with the consequences.
The Ba'ku /S'ona on the other hand are not Federation citizens so the Federation has no right to mess with them. Pre-warp or post-warp doesn't matter and you don't need the Prime Directive to realize that taking the land of resources of other folks is wrong. Gee, children learn these rules in the sandbox!
In short, there is no moral dilemma of any kind, INS is a simple, old-school, Picard vs. the evil admiral morality tale like The Drumhead. Like TFF it is essentially a small screen story, something thematically familiar from the series that doesn't work perfectly on the big screen.