Alex, Ivan, any name is fine ... there has to more than just one person doing this, it must be habitual, and they have to be in agreement. I would suppose that there has been a group of boulders who have now created a number of hard problems with chisels by now.
I remember watching a movie on that channel a few years ago that basically said something needed to be done that more routes could go up. At the time chisels did not enter my mind.
I find it strange that we do not know who took the video. Perhaps the group had some kind of falling out? If not, then why didn't the guy with the camera confront the guy with the chisel? I would have, and voiced my opinion on video. Hammering makes a lot of noise, at least the way he was doing it. It does not seem like he was very concerned about it, so why not confront him with the camera? Now we had to guess who it is until he admitted it.
The Mohonk Mountain House and the Mohonk Preserve have done a great job protecting the environment thus far, but ... it's all down hill from here http://youtu.be/9AU8fMo8v4k.