Your definition of "defamation" is incomplete and therefore inaccurate. It seems as though you are pulling stuff off the internet you think sounds good and then posting it here as definitive truth. That's a wrong thing to do. But since you like to rely on Google, from dictionarylaw.comNope. Your definition is too narrow. Someone is "defamed" when their reputation is diminished by someone else, and if you don't recognize that then I'm not sure what to tell you. The law allows an individual to address certain kinds of defamation (which you have focused on), and those lawsuits are in the category of torts concerning defamation, but that does not mean that other non-addressible defamation does not exist, because it does. If you disagree with that fact, then we'll have to agree to disagree.
And to kanzz's question, I choose not to discuss my personal background on the internet in forums. Given what I've seen in this world, I don't think that's wise. Instead I'm willing to offer what I know using my background and experience, and explain, and whether that's satisfactory to someone or not is up to them.
defamation
n. the act of making untrue statements about another which damages his/her reputation.
My underlining. Because it's critical that statements be untrue in order for them to be considered defamatory. And once again, Burke will surely not be considered a private figure with regard to his sister's murder; his voluntary nationally broadcasted Dr. Phil interview pre-CBS show sealed a deal that was already very likely. Not being a private figure means the burden is on Burke to prove the things CBS concluded about him were lies, were deliberate lies, and were lies made with actual malice.