"Personal Twitter accounts are dead" is a bit over-the-top. * He didn't make inflammatory comments that were un-related to work. He was directly commenting on

"Personal Twitter accounts are dead" is a bit over-the-top. * He didn't make inflammatory comments that were un-related to work. He was directly commenting on a rumoured feature of an upcoming product that he is over seeing. * He made no attempt to distinguish this as a personal Twitter account. On the contrary, he 'prominently' displayed his employer and position. * There's no reason that he couldn't have had a personal Twitter account without identifying information (i.e. pseudo-anonymous).