I don't think this lawsuit is going to happen for several reasons. First, King Kamali used pretty strong language in referring to it on the show... any attorney will advise against that. That videotaping thing sounds so bizarre and to me sounds more like something that would be used in a criminal case. If there was a threat from him towards you of physical violence, that is a lot worse than libel. But, to be libel it has to meet all of the criteria in the definition, which will usually consist of this but may vary in wording from state to state:
1. Presenting material to the public
2. by print, writing, signs, etc.
3. that is false (this must be proven, opinions are by definition neither true or false)
4. that damages a person's reputation (must also be proven).
Unless all are present, there is no libel. If you are sued, do not threaten to countersue by yourself, go through an attorney (which is the biggest reason why I don't believe him) because you can seriously screw yourself in how you word things. You may easily be able to get pro bono counsel through a free speech NFP such as the ACLU or a few of the newer internet free speech groups.
Also, this has to be taken in the context of his job as a bodybuilder in the public sphere and through his sponsors, the IFBB, etc. What are they going to think of this lawsuit? Message boards are undoubtedly a huge part of the bodybuilding fanbase... have any of the mags sued for copyright on pictures from them? I'm no expert on the law or bodybuilding, but this publicity for them could be lousy.