DS9 proved that the Federation people are, in reality, dirty slimeballs (how much lower can you get than committing genocide, and then refusing to stop it?!!!) and their alleged system of peace is just a facade.
Of course, despite putting that reality on-screen, DS9 also, totally inexplicably, tried to justify it, and pretend nothing is wrong with it. Like with the BS messages that the genocide is ok because a war is on, and that after it ends, Odo is going to be able to 'spread humanity' to and brainwash The Great Link into thinking humans are ok, despite the fact that they were just committing a genocide against them.
Not only is the very idea inherently ludicrous, is it also a bastardization of the Odo character himself. There is no way that an in-character Odo would have allowed the genocide to continue for one second, much less still believe that humans are fine and dandy after Sisko et al. have decided to continue the genocide.
In other words, the DS9 showrunners had the balls to show the Federation as it's ugly, evil true self, and then also tried to talk out of both sides of their mouths by reniging on that reality, and portraying the Federation is wonderful nonetheless. These are irreconcilable concepts, and the showrunners' attempt to reconcile them is made of epic fail.
Therefore, a choice must be made about which side of the showrunners' mouths to listen to. I personally reject the ludicrous and OOC stuff and go with the showrunners' original depiction of the Federation as slimeballs whose system is a facade, and Odo as a man of integrity who will always pursue justice at all costs, as the truth. I don't see how any other conclusions can be made. There is absolutey no way to justify the genocide against the Founders,
period. Nor Odo's complacency about it.
To add insult to (the Federation's) injury, that the genocide happened just goes to show that the Founders were right all along, and had great, totally legitimate reason to distrust and want to eliminate or subjugate all solids.