The 34-year-old left Madrid for Besiktas at around the same time Mourinho was installed as coach, bringing an end to over two decades of service, including his youth career, at the Santiago Bernabeu.
Guti says he does not approve of the trainer's attitudes, which in his opinion do not go hand-in-hand with Madrid's values.
"There are things about him that I do not like," Guti told Ona FM. "Madrid's principle is one of honour and that the club must be over the people.
"Mourinho is a person with a strong character, who defends what he thinks until death. That is good because, without that, you are devoured in football."
Mourinho came under fire for his part in the brawl which took place in the closing stages of the second leg of the Spanish Supercopa as he poked a finger in the eye of Barcelona assistant Tito Vilanova.