Re: Why is it
The defense got no pressure on the qb. One sack, which generated the first defensive turnover of the season 12 quarters into the season. They still have zero ints. That's against J. Flacco, Tavarus Jackson, Kerry Collins & Curtis Painter.(Meabwhile the Bills intercepted Brady 4 times...wow!) They were getting gashed by the Colts rushing game. They were very fortunate that Painter overthrew Garcon on that play. And they allowed a bad 3rd string qb with no game experience to lead an 80 drive down the field at the end of the game, and frankly, he made it look easy.
So, while the offense deserves their share of the blame, the defense has not exactly been stellar. In fact they've looked rather pefdestrian for the most part. While they are not THE problem, they are certainly part of the problem, and certainly not providing a whole lot of solutions in the form of turnovers, sacks, and the like.
Right now, this whole team is stinking, through and through, with the exception of a couple individual efforts in each game. Offense stinks, defense is mediocre and special teams aren't really doing anything all that special. And the whole coaching staff(Tomlin, LeBeau and the guy who calls play for the offense), has done a bad job thus far, of having this team ready to avenge last years SB loss.