This is one of the subjective rules that is rarely enforced, which is probably why it seems surprising for a player to receive a penalty doing something that happens regularly without penalty. The key is that in this case the player was warned multiple times, so it is entirely fair for the penalty to be enforced after ample warning. I'd say that even if the warning itself was unfair!
I suspect the reason the rule is rarely enforced is because people rarely complain about it. For advanced players being on the receiving end of endless banter oftentimes helps, as you have additional information to consider.
Case in point, I once had a non-stop "talker" similar to this while I was contemplating my decision to call or fold with a very mediocre hand that could only beat a bluff. The dealer actually asked the talking player to stop talking, but I said, "No, please let him talk. I enjoy it." (Which by the way, I think put the player a little on edge.) After some thought I figured the only reason he wouldn't stop talking was because he was nervous I might call. I finally decided to raise just in case he had a better mediocre hand than mine, and he folded. He then said something like, "Why you'd wait so long if you were gonna raise?" which I loved because that meant he thought I had a strong hand, which was my exact goal. Neither of us showed. I bring up the hand because I'm pretty sure I would have folded had he not been talking so much, which in this case helped me.
Along the same lines, (and an aside from your question), an interesting take away from that video is a great psychological lesson:
The player has been warned, and risking a penalty, is still talking and/or gesturing. Why would he do that?
No sane person would risk a penalty and/or potential monetary loss for no reason. They only would do this if they are scared of something. Generally people are not "scared" of someone folding, even when they have the nuts. That would be "disappointment" of not extracting as much money from the hand, but not "fear". The only thing to be scared of is losing the hand, and the only way that can possibly happen in this case is if she calls. So it's obvious that she should have called. Note that isn't true at the time he made the bet; it didn't become true until he repeatedly tried to encourage her to call/fold (it doesn't matter which). You could argue maybe if he had a strong hand he would do the same thing using reverse psychology to entice a call, but after being warned to be quiet and still carrying on, I think it's pretty obvious that he was pretty scared of the call, which means she probably should call here.
