> However, as a practical issue, I fail to see any practical reason to disable the guy's revenue from YouTube videos . . .
Really? I have thought about it for about two minutes and came up with several.
1. Google might assume that someone who has committed click fraud in the past might do so again, and preemptively remove other facets of that person's ability to harm the system.
2. Google might want to discourage people from committing piecemeal fraud by ensuring them that there is no way to risk just part of your account with Google. By disabling all of this guy's ability to make money from Google, they are sending the signal, "Hey, don't think you can pull a fast one and still keep any part of your business with us, even if the site is unrelated."
3. Maybe there was some undisclosed badness going on with the Youtube account that we are not seeing in the account given in this article.