Right now the defense is subpar at best. I don't care what the stats say. All I know is what I see and lately it ain't pretty.
Game 1: Close game, punter pins the Bears deep, the defense doesn't allow a first down and closes with a 4th down sack. Defense wins
Game 2: Held the a team averaging 26 points/game to 16 points, not allowing a point after part way through the 3rd quarter. Forced the Vikings to go punt, punt, interception, punt, fumble to end the game. Defense wins
Game 3: Again with only 5 minutes into the 3rd qtr, the Broncos score their last points. The Packers defense forces an INT, punt, turnover on downs, and ends the game with a sack. Defense wins
Game 4: Not a good game - allowed 34 points. Defense loses to the Eagles
Game 5: Also not a good game - but only allowed 24 points. Best defensive play was in the first half, aside from the Kevin King INT in the second half and stopped Dallas for a FG attempt when they needed a TD.
Game 6: For as much as the Lions moved the ball, they got one TD on the day. The rest of the time Packers held them to punts and FGs. Defense wins
Game 7: From the mid-point of the third quarter the defense got a turnover on downs, an INT, forced a punt, and then gave up a late TD in garbage time to the Raiders. Defense wins
Game 8: Against a high octane offense (even without Mahomes), they only allowed 17 points in the first half. After that the defense forced punt, fumble, TD, punt on its way to victory. Defense wins
Game 9: Rivers always does well against Green Bay. The defense held him to FG, FG, punt, FG in the first half. The defense kept us in the game at 9-0 despite the offense laying an egg. They even held the Chargers to another FG to start the second half but then the dam broke as GB continued to struggle on offense.
I think all that you are seeing is the stats. You see the other teams moving the ball and getting yards, but seem to be turning your head every time the defense holds tight and clamps down. We aren't the '85 Bears or '00 Ravens but we also aren't the 2011 Packers. The defense can improve but they are doing what is most important, keeping teams out of the endzone. That's a stat that you should care about.