Gotcha, my bad. I read that one wrong. Either way, we're now arguing about the Giants' run defense, aka 3 orders of magnitude removed from the original point, which is whether or not Denver's any good.
If you want to know why Denver's doing well, it's because their defense is much better than ours, and their offense is at least on par with ours; marginally better, even, IMO. They have more proven weapons than we do, and they also have some elite young talent that stands to improve its contributions as the season goes on (Moreno recovering, Demaryius Thomas improving). As a Patriots fan, there's not a whole lot of reasons to be encouraged by the Broncos' success. To assume that we have a far better offense than them is a deeply flawed starting point.