Judging from his behavior I think its likely a personal choice. It is still highly unprofessional and disappointing the way he has behaved, just the same. Its also cause for concern when any higher up in an organization that is supposedly built upon the concept of promoting free speech chooses to act in such a manner. The hide feature, as used by heavy hitters, is essentially a form of soft censorship regardless of what @sneak tries to state otherwise. @valued-customer's posts in this thread sum it all up quite well.