I can't remember where I read it, if on HN or elsewhere, but that was what I heard, it sounded plausible enough. I guess it was likely another excuse. At the very least they're aiming towards the bleeding 'Edge'.
It originally comes from the IE Blog in, I think, the IE7 release cycle (my memory of the date could be wrong; it's certainly a while ago!). At the time almost everything there was pretty censored and overly-dressed-up.
