He quite possibly could have left, or just simply logged out so his profile doesn't update 'last active time' and is still reading. Sorry for the awful conspiracy theory, must be contagious somehow.
I guess without any background music the videos will quickly 'feel' empty. Because at that moment it's basically an annotated screen capture of someone typing out a bunch of code. However, I agree that I like to have my own choice of music and very often turn music off in any utility, game or whatever I play.
Additionally I wonder if video is the best way of communication for code tutorials. I've been programming since I was 12 years old and never watched coding tutorials. Personally I think coding is best learned from text unless there is a continuous flow in the video for the viewer to experience, and even at that time it's very hard to follow.
Look at mythbusters. Count the number of computer myths they have done. That's like 1: pilot episode "Exploding CD's". Everything related to electronics and computers is hard to visualize for the mainstream. I think in this case it's similar, as code is just a bunch of text without much meaning from a large scale, unless you read line by line.
Then again, very often video is not the optimal way of communication so in that sense it's just a preference.