Well, now they have it straight from the horse's mouth, so to speak.
I'm not sure whether KC is telling the truth or not. She could be. But, my own (elderly) mother has always been a sociopath and when she tells a lie she ends up believing her own lie, even years later. Example is my mother once claimed a phone company repairman made sexual advances and theft in order to get him in trouble over him reporting an illegal line--she admitted the lie to me before she told it but now even to this day she claims he did this. So with KC, with her telling others about sexual abuse, even if it was a lie to get back at LA and/or GA in the beginning, it could be she now really believes her own lie.
Of course, there's a chance she's telling the truth too. Thing is, she's been caught in other lies so even if it's true she won't be believed. And of course the rest of the A's would deny something like this--I mean, in their shoes so would I. (not that I'm sympathizing, I'm not).