Didn't say they were murderers...said IMHO they covered up her accidental death to cover the Demons butt on sexual abuse.....
If she died "accidentally" as a result of abuse, then they're guilty of her murder, at least in the second or third degree.
By the same token, if JonBenet died as a result of Patsy Ramsay's hitting her, and Ramsay covered it up to make it LOOK like an accident (as was alleged in the book that came out a year or so ago), then she is guilty as well.