I'm no fan of Stern, but the Warriors situation is different. I don't like tanking for picks, or the idea that failure is rewarded. The Warriors, as do many teams, decided to get season ending surgeries out of the way before the season ended.
That strongly differs from sitting the starting lineup on a random day. You want teams to put in the best effort in each and every game, and not just throw a game. There are considerations of short term versus long term goals, like the Warriors had. But the Spurs situation can hardly be argued as achieving long term goals, not at this point of the season and under 30 guys being sat.
You want to give your team the best opportunity to win a championship, not a single game in November. There have been all sorts of studies done, and every single one of them has conclusively found that the single biggest risk factor for athletic injury is insufficient rest. The Spurs core lineup is made up of old players; Duncan is 36, Ginobili is 35, Parker is 30... these aren't 21-year-olds who can bang every night with no ill effects. If you play Duncan and he ends up getting a season-ending injury, are the Spurs really in a better position to win a championship? Of course not. So there's really no reason to risk your star players' health when playing 5 games in 7 nights, 4 of them on the road (which is a fucking stupid schedule, by the way). Here, let's take this old-ass team and give them two back-to-backs with a single day of rest between them that requires traveling between Canada, Washington DC and Florida.... The game represents 1.2% of the Spurs season (not including playoffs); it's probably not going to sway their odds of making the postseason.
Stern's position on this is 100% indefensible. He has not enforced this rule for any team in the last 20 years, and all of a sudden he drops the hammer to the tune of a $250,000 fine. Where's the logic in that?
And, lest we forget, this Spurs team that obviously was trying to throw the game by not playing their star players somehow managed to lead the game with mere minutes left. It took a clutch three by Ray Allen (who is known for that sort of thing) for Miami to win. So let's not lie to each other and say that the Spurs threw the game. They were competitive throughout. If they had won, would Stern still be fining them?