The biggest surprise of the NBA’s shopping season came by self-delivery. The Warriors didn’t walk into a meeting trying to persuade DeMarcus Cousins to please consider joining their team. He showed up on their doorstep. They simply decided, well, OK, why not? And that has touched off howling and screeching and cursing throughout the land. The Warriors, relentless rascals, did it again. The back-to-back NBA champions, with four All-Stars on the roster, are adding a fifth. Already poised to lap the field, the reaction to them welcoming Cousins has been broad indignation, as if they’ve turned around and started running backward, laughing at the chumps in the distance. The amount of animosity being slung their way can be weighed by the metric ton. They’re breaking the NBA! They’re ruining the game! They’re taking all the fun out of it! Is there no line they won’t cross? Where was all this when the Warriors were losing 33 consecutive games in San Antonio? When they were 11-30 over a 10-year stretch against the Suns? How about the 17-season span, 1995-2012, when the Warriors were 12-55 against the Lakers? Suddenly, the Warriors are living in sporting waters that have been relatively calm since…