I wouldn't completely dismiss the videos as it really needs only be one case of seeing the same actor to know this exists.
This is his argument, and he'd like to use it, but he's going about it in the wrong way.
He wants to show 'all' these stories are fake, but to do that, he would have to prove each and every one, which is obviously not going over well. So he uses the (noted above) justification, which separates him from the system of logic he so desperately wants to use.
He would have been better off to assume that 'all' of these cases are genuine, then all he would need to do is show one to be false and he could use the justification (noted above) to negate his assumption.
That wouldn't be as sensational as what he's trying to do, since he would really only be able to say that one of these (specific) cases are not genuine. But at least he would have something to stand on.
I think most people know what they see on TV is not real, maybe just not to the extent that it actually is(n't). Here's a little something from a studio:
[ame="http://www.youtube.com/watch?v=clnozSXyF4k"]Stargate Studios Virtual Backlot Reel 2009 - YouTube[/ame]