Rodgers only does the head first dive/slide when sliding would likely cost him a first down. He still gets down quickly and, I think, leads with his left shoulder. That reduces the contact that he takes. Also since the rules about slides mean the defensive players are not likely selling out for the big hit. While he still needs to be touched when on the ground, the biggest risk is from a helmet hit, and spearing is still a penalty. I do cringe, but he is smart about it.