Yeah, Scott pretending MMR doesn’t exist is very frustrating. I think he’s trying to keep it simple for the plebs, but it isn’t really working. At this point, I consider Seagull & Jeff Kaplan: NEW Hero Confirmed! - YouTube to be definitive that SR has no effect on matchmaking.
I have seen the talk. It is good. http://www.moserware.com/2010/03/computing-your-skill.html is also good.