Don't get me wrong, I don't like it either. That's why I made this thread
I was vaguely aware of the rule you posted but haven't really seen it enforced in a very long time, at least as far as indie projects that don't appear to be a scam are concerned.
Truth be told, I was actually wondering why the ban hammer didn't come down on him back when he started but have since come to the conclusion that hes not really doing any harm by advertising his channel, especially since he walks the line by starting a discussion that usually gets a post or two on topic, so that's probably another reason why admins let him be.
I'm somewhat less vindictive towards this kind of "spam", because I get that it's not easy getting an audience for your content. I've watched bits and pieces of his videos and while they aren't anything amazing or something I would watch on a regular basis, you have to start somewhere and its obvious that some effort went into creating them.
If you have a channel, you have to find some way of telling people about it, and this seems like the right place for the content on offer.
Long story short, right forum, wrong section.
It does annoy me though...