Well there are a number of things. First, defamation where you are is presumably different than here. I believe there is some absolute malice requirement or something equally wacky down there that doesn't exist here thanks to Hill v. Scientology. The USA is generally pretty bad for copyright protection.
Second, there are interesting jurisdictional issues because that was played not only on TV which is accessible in multiple countries but also the internet. There is emerging OECD model law on this kind of stuff but I understand it's underdeveloped for obvious reasons and I'm not an IP lawyer so I don't know, to use a technical term, jack shit about it. Essentially, though, even if his case was weak under US law, that's not to say he couldn't sue in Canada, where I and thousands of others saw it, or France under the civil law of that country, etc. In Canada and many other places, I am pretty confident a moral rights claim has some legs, if nothing else.
One thing you have to understand about boilerplate is that a large amount of it means nothing. Example, go park in an underground parking lot and the ticked you put on your dash will have a bunch of liability waivers printed on it. You'd read it and think "shit, if something happens I'm screwed", but exactly none of that is legal. If you sign a commercial lease for retail space, if you actually read the lease terms it's one of the most ridiculous types of contracts you can imagine, they have stuff in some of those that provides that the lessor revokes all rights to not get physically assaulted (not kidding, have seen this). Then there's a provision at the end that makes all illegal provisions severable - i.e., if something in here ain't cool, just ignore it. It's essentially white noise. That stuff is everywhere. What TruTV puts in the fine print somewhere on the website or at the end of their credits to attempt to cover its own ass does not necessarily make any difference whatsoever.
Being "misinformed" and "wilfully blind to the truth" are very different things; arguably a failure to engage in at least some due diligence to ensure that any story they publish is true is negligent in and of itself but I am pretty positive that "well someone told me this shit so I published it on the assumption that they weren't full of crap" is not a particularly effective defense to defamation - or anything else for that matter.
This is all nerd talk anyway, this shit happened in 2009 so it'd all be statute barred now in any case. Pretty much BS though, I hope he did talk to someone about it. Like I say, this isn't my area of practice, but if someone pitched this shit to me now I'd run it by one of the IP people for sure.