Dude. Sometimes the numbers don't tell the story, sometimes they do. Jacksonville's defense is 22nd because most teams can stop playing after the 2nd quarter.
edit.- and, Jesus, they have played some bad teams. Jets, Houston, and Atlanta in the last 6 weeks. They lost to the Jets,, Atlanta, and Houston, in fact. They have 10 double digit losses. This team is really an awful team.
Yes, Jax has been terrible. They've also beaten Miami and Buffalo. Go figure.
And your take that their opponents stop playing after the first half isn't really true. (what a fun rabbit trail this is, btw!) Here's their game-by-game score at the half:
at Hou (L, 37-21): Hou, 27-7. Verdict: Yes they probably eased up on the gas at that point.
vs Den (L, 23-13): Den, 10-7. Verdict: No way did Den take their foot off the gas. They put up 10 points in the third quarter.
vs Ari (L, 31-19): Jax, 13-7. Verdict: Obviously Ari didn't take their foot off the gas. Nor after the third, at which time the score was 24-20 Arizona.
at Cin (L, 24-21): Jax, 14-0. Verdict: Obviously Cincy didn't take their foot off the gas.
vs Ten (L, 37-19): Ten, 24-13. Verdict: No way did Ten take their foot off the gas. It was still a game at that point.
at Mia (W, 23-20): Mia, 13-10. Verdict: No way did Mia take their foot off the gas. In fact, they lost the game.
vs Sea (L, 31-7): Sea, 17-0. Verdict: Maybe Sea took their foot off the gas. But probably not until they scored again in the third to make it 24-0.
at Buf (W, 9-6): Tie, 6-6. Verdict: No way Buffalo took their foot off the gas.
at Ind (L, 23-17): Ind, 20-9. Verdict: No way Indy took their foot off the gas. They may have felt like they were in pretty good shape but they didn't stop trying to score. That was still a game. In fact, Jax cut it to 20-17 before Indy kicked a FG with just over 2 minutes left.
at SF (L, 30-10): SF, 20-3. Verdict: SF may have eased up after the half. But again, probably not until they got a TD in the third Q.
vs Atl (L, 21-14): Atl, 14-3. Verdict: No way Atlanta would have eased up on the gas.
at LAR (L, 37-7): LAR, 16-7. Verdict: Rams didn't ease up. They poured it on, in fact, in the third quarter. They scored 21 second half points. They didn't ease up - they went full throttle.
at Ten (L, 20-0): Ten, 10-0. Verdict: The Titans didn't ease up after the half, not up just 10-0.
at Hou (L, 30-16): Hou, 20-10. Verdict: the Texans probably didn't ease up at all. In fact, with just 2:22 left in the game, Mills threw a 43-yard TD pass to Cooks. Clearly they were still trying to score, otherwise that play wouldn't have made any sense at all.
vs NYJ (L, 26-21): NYJ, 13-12. Verdict: obviously the Jets weren't easing up at all.
at NE (L, 50-10): NE, 28-3. Verdict: yeah, NE probably eased up, but it wasn't til the 4th quarter when they put Hoyer in.
So there were a lot of double digit losses by Jax this year, but there were only like 2 games where their opponents probably eased up after two quarters.
