I think you're putting a little too much stock in that "worst team in football" tag. Before 2003 that was hung on the Bengals and they thumped us in 2002. The difference between the best and the worst of the NFL is much smaller than you might think.
I was simply addressing the question of why our defense isn't the aggressive death dealing monster that some people feel it should be. It looked pretty good in 2002, suffered losses and showed how thin it was in 2003, and now it's been tinkered with to address that situation in 2004. Give it the first 4 weeks of the season and when we've wrapped that up see if you think any progress has been made on this side of the ball.
Why we lost the game was a completely different question. My answer to that would be that the Chargers took advantage of a pair of costly fumbles and a couple of interceptions. They got 14 points off of turnovers (and could have had more) while we were shorted 4 potential scoring opportunities. Simple as that. Our players didn't do their jobs on the offensive side of the ball consistently enough to win.
Fitz makes bad decisions. That's not going to change.