Just a couple of ideas,
1. any footage that you are in you can use, the filmer doesnt own you.
2. Christo said himself, he didnt shoot it, N***** did and she is ok with it being posted. As for the film being a work of "Art" or created property, it is hard to claim ownership for the film in whole as it was posted when christo was not the filmer or the editor. imagine that...
3. Newman's not profiting from it, they cant sue for money, the worst they can make you do is take it down (if he can even prove he owns it, not being the filmer and all..). The only way that christo can sue for money is if the footage being posted is preventing him from gaining profit, again not likely since he is apparently handing it out for free to friends and isn't the owner himself since he didn't shoot it.
4. as a registered non-profit organization (legally a type of business) any kind of smearing on these public accessed boards is slander (yes what he is saying is a harmful lie since he is yet to prove that he actually owns anything), newman can sue christo. (what he can sue him for I dont know, but he seems to have more of a right than christo does at this point).
And in response the original post at the top there, what exactly do you not agree with "what is being supported" by the website? Are you suddenly anti-kayaker?