Rodgers said that he was shocked that Ferguson showed a complete lack of "old school values and ethics" when he criticised former players and rivals in his autobiography.
Ferguson issued a withering critique of Liverpool icon Steven Gerrard, saying in his book that, "I'm one of the few who believes he isn't a top, top player."
That criticism came despite Ferguson having tried to buy Gerrard in 2005, and despite having called him "the most influential player in England" earlier this year.
Rodgers called the judgement in Ferguson's book "more than harsh" - but it was the criticism of United's former stars that raised the Liverpool boss's eyebrows the most.
"Anyone who's been in football knows that whatever is said behind closed doors and in the changing room is something you wouldn't want to hear again," Rodgers told TalkSport.
"It's something that's vitally important. You want to know as a human being that you can speak openly and communication is honest, and hopefully wouldn't get repeated.
"You would like to think you would still have some old school values and ethics that whatever is said you take it on the chin and keep it behind closed doors and move on."
Rodgers, speaking on the Alan Brazil show, clearly found it difficult to see where Ferguson was coming from with his assertion that the midfielder was "not a top, top player"..
“I think everyone who’s seen the comments will think they are harsh," said Rodgers.
"I’ve watched Gerrard for many years and recognised he’s a top player but it’s only when you come in and work with the man that you realise how professional he is on a daily basis.
“His performance level at 33 years of age shows he’s a top, top player.
"He’s a great talent, a wonderful player and I don’t think anyone could argue against that.”