I wouldn't say Rodgers instilled a loser mentality. For all his faults, until his final season, we done well under him, and maybe if the board had backed him in the January transfer windows of the 2 seasons we dropped out of the champions league places in the final week, we maybe would not have not dropped out, and had 2 seasons of champions league money to put into the accounts.
Rodgers chucked his toys out of the pram at the start of his last season, because the board wouldn't back him, much as he has done with celtic this season. He checked out long before he went, and should have been gone long before he was that season, because his checked out mentality filtered into the players, which is why we went down with a team that shouldn't have been anywhere near the bottom three in my opinion.
From that point, the lack of leadership, accountability, and basically having any idea of how to run a football club, at the top of the club, has created a lazy, here for the money, I don't care attitude amongst the players, which does indeed mean they have a loser mentality!