I don't have a problem with resting the starters especially if they've secured a playoff berth. The second string is going to go out and PLAY. I'm not calling for a team that's already clearly won the game to go out and slaughter the other team, either, just 'cause they can. It'd be different if the Chargers were back by even a full touchdown -- though I still think they should have play the games out, and not just take a knee and let the clock run out. Something just ain't right when there's 30 seconds or so left, and the teams are out there shaking hands.
But, c'mon, is it conceivable that the Chargers could have made an interception or picked up a fumble, and either tied the game or even won? Sure. It's not likely -- but it's possible. Let 'em have that chance! Instead, this is kind of loosely like a baseball game where home team is leading by 1 run in the top of the ninth, so they only play 2 outs... then everyone quits 'cause that third out "doesn't matter"... it might have been a home run -- or a grand slam...