Something along the way may have opened his eyes a little that society needs to be open, that debate, discussion and disagreement are needed because people will never all view things the same way. He also might just feel the tides are shifting, the pendulum is on the edge of swinging back, and he doesn't want to get left behind. Or it is none of that... just Trump and the GOP getting really pissed at all the censorship might have been enough to scare him into supporting sane free speech policies. Seems twitter/reddit/others want to keep poking the sleep giant though.