The Federation treated the Klingons with care because, again, a full-out war with them (as shown) was a losing proposition for both sides, especially with The Dominion waiting to mop up anyone who survived. It's easy to say the Feds shouldn't have made peace with the Klingons; what would you have preferred, exactly?
Once the Cardassians joined The Dominion they attacked The Maquis so swiftly that there was nothing left to defend. It's likely the Feds took in Maquis refugees, because why not? Wouldn't mean they shouldn't face charges for any potential crimes they committed during their "holy war", though. If the Maquis actions weren't religious (and in the case of the Native American types...) they were certainly based on ideology more than practical reasons.
Please cite some supporting evidence for claims that the Feds were heartless regarding the situation.
I was not suggesting that the Federation should have declared an all out war against the Klingons.
I was making a comparison between how harshly the Feds treated their former compatriots, the human settlers (whom the Federation sold out in the first place), and how forgivingly the Feds dealt with the Klingons, who committed naked aggression against DS9 and the Federation.
I suppose it was also somewhat ironic that it was the aggressive action of the Federation's good buddies, the Klingons, that led the Cardassians to eventual war with the Federation, but not the actions of the Maquis.
Sisko was so fearful that the actions of the Maquis would lead to a war with the Cardassian when it was primarily Klingon aggression against Cardassia that made the Cardassians feel vulnerable which led to their alliance with the Dominion and thus all out war.
The Klingons deserve contempt not the Maquis.
During the Klingon invasion of Cardassia, they seized a number of Cardassian planets and outposts. Oddly enough the Klingons held onto them even as they remade peace with the Federation. I assume the Klingons defended those Cardassian territory that they seized through aggression, while those in the Federation, like Sisko and his ilk, probably couldn't have care less as the Cardassian/Dominion slaughtered their former human compatriots.
As contemptible as the Klingons were, I can at least respect them for defending what they think is theirs, while I can not respect the Federation for what I assume was a second betrayal of those human settlers by the Feds when the Feds apparently did not come to their aid as the Cardassian/Dominion slaughtered them.