Buses are flat, so they tend not to scoop you up and fling you, so much as knock you flat (having been hit by both a car and a bus, I speak only from personal experience). I think that might have something to do with it. I suspect that the "grazes and bruising" may be more severe than the reports imply. Three weeks on from hitting the tarmac myself at lower speed, I have an elbow that's still pretty tender (but irritatingly, not troubling enough to make me remember not to rest on the hurty bit).
I wish the news media wouldn't minimise incidents like this - I suspect that this bloke is going to be very uncomfortable (to say the least) for not less than a month - not to mention that he'll be questioning just how bad this could have been for a long while.