Valdano was shown the door after failing to work well with the coach.
Mourinho is thought to still have the backing of supporters, something Calderon was keen to comment on.
"You can have millions of fans cheering for you, but Hitler was also acclaimed by millions of people before he took a tumble," the lawyer told Catalan radio station ONA FM.
Calderon was also keen to offend current president Florentino Perez on his ability to run the club.
"I feel sorry for Madrid and Florentino. Yesterday [during the announcement that Valdano will leave Madrid] I had the sensation of seeing a student who didn't know the lesson taking a primary exam," he added.
"They talked so much about dysfunction that they may as well of been talking about erectile dysfunction. It reflects a pathetic picture. It was like seeing a corpse in search of a coffin."