This idea of Sarri not getting backed is stupid. If he hadn't been backed, then WTH were those signings of Jorginho, Kovacic, Higuain about?
Those situations involving the fans booing him weren't great, but if he can't take a bit of heat, a bit of criticism (especially when some of it was his own doing), then maybe he shouldn't manage a club at the highest level and go back to manage in Serie B or C or something.
The Napoli fans might not have booed him when he was there but managing Napoli and Juventus is two different worlds altogether. Good luck to him if he thinks things will be all rosy at Juventus if/when things go south.