Mourinho losing once and the fans are going crazy... . In my opinion, Mourinho saved Roma when he came and the entire city knows it so even if you like Mourinho or you don't , he is one of the greatest coach ever who didn't back down from a challenge like coaching As.Roma when the team was in a free fall. Also , they are the champions of Conference League so I suppose they can afford to lose 1 game...
Don't know what happened to the fans of this Club because as you said when Roma lost a game they were busy criticizing Mou but when they won and last season the trophy was brought not a few of them criticized it straight away.
At the moment, even though Roma's performance is still pretty good despite the defeat, it's actually quite reasonable but the fans think it's an unnatural performance for Mou for Roma.