Motta was sacked and replaced with Igor Tudor on Sunday afternoon by Juve.
In reaction, Adani told Domenica Sportiva: "After the defeat against Fiorentina, the team seemed to be able to be united in the difficulties. At least that's what it seemed.
"Then in the week where the international players are not present and with the coach on leave for a few days, you decide to change the technical guide.
"He must have discovered it in the afternoon, after a series of published articles: as far as I'm concerned, it was an amateur management from the club. The problems do not come directly from a technical management, but from the club."
Former Juve striker Nicola Amoruso, meanwhile, told TMW: "He drew many games that he should have won. If he had won them, we wouldn't be in this situation. We also know that whoever arrives at Juve must aim high and always win. The history, tradition and value of the team demand it.
"Thiago Motta no longer had the situation under control. And so we went in the direction of dismissal."
On former Juve teammate Tudor, Amoruso added: "I'm very happy. Igor is a friend and could be the right person to lift Juventus out of a negative moment. He also has the advantage of knowing the environment very well.
"A few days ago I sent him a message telling him that he would be the ideal coach for Juventus. He replied without committing himself. And now the moment has come. I'm confident. Igor can do well."