This episode is a perfect example why the writing in DS9 (apart from some quality bits involving the Cardassian and Ferengi related episodes throughout the series and the Dominion war arc that's basically the only interesting thing about the show) is simply below par and inferior to, say, TNG. While the majority of the episode is reasonable in describing the Defiant missions in the war against the Dominion, the resistance cell actions on DS9 aka Terok Nor, it fails miserably at the end, in terms of keeping the Odo character consistent with the previous 5 seasons. The latter alone destroyed both the episode and its conclusion, really.
Without spoiling it, it's simply inconceivable that a character that devoted his life to justice and, by extension, peaceful resolution to disputes (remember, he refused to carry weapons on him as the Security chief), who has an unwavering attitude of rejecting a vast array of temptations offered to himself, a character that developped more than friendly relationships with the "solids" and who holds one's responsibility and accountability - including his own - in the highest regard ... to do what he did at the end of this episode, not to mention THE WAY in which he did it. More specifically, I'm not talking about siding with a Founder once in a while (because that's understandable, after all, they belong to the same race), I'm talking about doing that irresponsibly and without caring for the repercussions of his actions. It's like having an episode where Odo looks away and doesn't bother to investigate and find the murderer of another individual that happened under his watch ... because he just doesn't give a f.... about it. Especially when the same (dumb) writers emphasized his responsibility and professionalism with every occasion throughout the series.
Lastly, Odo doing such things after just two "sessions"/meetings with another character is absurd, considering he had at least two of such encounters in the past with the said character and was clearly unfazed at this level before.
Bottom line, the writers (again) chose to suit the story after the desired result instead of modelating the result based on the story. Apparently, for such amateur writers, it's the effect that determines the cause, and not the cause that leads to a certain effect. And, of course, the whole plot is not only overly simplistic and ridiculous, but utterly not believable. The resolve is insulting the intelligence of the viewers, plain and simple. This could have been done in a million of better, more intelligent and more believeble ways than foolishly playing Odo out of character, really.