I agree some AX's are capable of doing things, including sexual abuse, to spite the other parent or to cause a reaction, drama, or anxiety.
I do not agree that holding two equal possibilities in mind - accident or intentional - is codependent enabling. We often don't have all the facts.
Unlike if it was a neighbor letting them see porn, when of course we'd never allow them to go there again, many of us are court-ordered to turn our innocent children over to these negligent (at best) or heinous alcoholics - because absent them being found by a court to be abusing the children, we can do nothing. The entire system seems geared to "give the alcoholic the benefit of the doubt" versus "protect the best interests of the child."
This is especially terrifying to moms who have young kids, one kid, or a kid who clams up and won't share what's happening. So sometimes, holding the two possibilities in mind is the only thing that can keep us sane.