Combination of things going with the Ants, imo.
(1)They blame themselves for whatever happened after the big blowup, after using 'tough love.' The Creature had stolen and lied. They'd had enough (JUSTIFIABLY.) They were finally ready to act, but when they did....whatever happened, happened. Now Caylee's gone and KC's in jail, most probably guilty of murdering Caylee. The voices in their heads keep saying (among other things) that if only they hadn't brought things to a head, everything would be ok. This would be tough for any of us, but they won't face up. Facing up is important because once they do, they can move beyond guilt to deeper understanding. It's unacceptable to let one's child go on thieving and lying forever, especially when a child is involved. KC's irresponsibility was bad for both herself and Caylee. The Ants were right to try to stop her and set her on a better path. They didn't kill Caylee. KC did whatever she did, not because she was held accountable but because she couldn't an accident responsibly or because she's capable of murder. If the Ants can accept that, they can see they tried to do the right thing and take some comfort from knowing that it's good to try to do the right thing.
(2) If they know what happened, because somehow they've accepted it, or KC has told them, or (God forbid) they played some part in a cover up, then they may think or may know they raised a murderer, and feel guilt and shame for that. Maybe, they don't want anyone to know and they want to do whatever they can do for KC because she's all they have left. Yet, if they could face what they think or know, they could put a higher good above their own interests and guilt (Caylee specifically, society in general.) Look at the Unibomber's family. They read a manifesto, thought it sounded like Ted and started talking to the FBI. The FBI caught him and lives and limbs have almost certainly been saved. They probably feel rotten that one of their did these awful things, but the can at least have some peace knowing they stopped him from doing more harm and allowed justice to be served for his victims. If the Ants could truly put Caylee above KC in their own minds, I think they'd understand that they need to face the truth and move forward FOR CAYLEE, to memorialize her, to bring the person responsible for her demise to justice. Then they'd have the peace of closure knowing they did they best for Caylee they after something awful happened. However, they just don't seem to be able to muster the courage.
(3) Imo, the Ants have been playing games from Day 31, trying to get the truth out of the Creature From Adverb Lagoon. Prior to that, there are indications that the Ants were not at all happy with KC and her choices and not shy about telling her so. We have Jesse telling the police that Cindy often insulted KC in his presence. Amy said the same thing. When she was in the car with Cindy, Cindy was disparaging KC almost the whole time. Ryan said Cindy called him to tell him that KC was a sociopath and other bad things. When Cindy got to TonE's, she told him KC would steal him blind. Cindy's mom is writing her relatives talking about KC's various irresponsibilities and crimes, almost certainly because Cindy had been telling her mom, and because they'd all been victims. KC told Lee she needed alchohol to put up with her dad at a family celebration. Then, there was the big blow-up fight. It wasn't all gooey sweet at the Ants. KC had thrown her parents under the bus all over town. Cindy was apparently capable of coming down on Casey like a ton of bricks, but to look at the nicey, nicey interaction with KC holding court in the jail visits, one would think that there had been an outer-space invasion, and that these people had been body-snatched. They are either trying to present a false face to the media, police and public or the Ants think if they can convince KC they love and support her, no matter what, she'll tell them where Caylee is. They want to think she's alive early on, so they do. Maybe some psych told the Ant that they had to handle KC without confrontation because of her personality disorder. Who knows? Whatever, doesn't seem to have worked. It's horrid what KC has done, and is still doing, to her parents.
(4) The Ants seem to have gone downhill drastically in the past couple of weeks. Their appearance deteriorated and they went silent. Maybe they know something that we don't know yet. Perhaps dropping the DP is part of it. Perhaps Jose is in negotiations. Perhaps the Ants know that. Perhaps they know why.
