The only consideration I can think of even close to the insightfulness of komponisto's analysis of how the coverup is the only hard question in the Knox case

Naturally, I greatly appreciate the compliment and the link. (Thanks!) However, I have to point out that this isn't a correct summary of that post. A correct summary would be: "the burden of proof for demostrating a coverup by Knox and Sollecito is as high as for demonstrating their guilt of murder". I don't claim that the question of whether there was a coverup is particularly hard to resolve (to the contrary, the aforementioned claim implies strongly that there almost certainly wasn't a coverup), and nor do I compare its difficulty with other aspects of the case.

ask how often mothers cover up a murder of their children they were not culpable in

As I understand it, the principal defense theory in the Anthony case is that it wasn't a homicide at all, but an accident that was covered up.