The Denmark wing-back joined United for a fee rising to €38m on Monday's deadline day.
He told Calciolecce.it: "Let's start with the Dorgu operation which has the characteristics of the extraordinary. It is our record sale and it happens in our moment of great economic health. Someone wanted to talk about critical issues, which have existed but in the past with covid on whose recovery I will return later.
"It was not a planned operation, it was not done to fill critical issues of the past. It brings us wealth from all points of view and the possibility of making technical and structural investments.
"We said several times that Dorgu would not leave in January, and now I will explain why the opposite happened. Then Manchester United arrived, who made themselves heard with us and with the boy's entourage, receiving an official response from us that I leave here, in which we said that we had no intention of letting Dorgu leave in January. And not talking about figures, not asking for increases. This, instead of stopping United, had the opposite effect. Manchester insisted, we asked several times to postpone everything until the summer, also promising the young man that he would not miss the opportunity.
"For us too it was a historic step, we just wanted to do it in July. The English communicated to us their desire, the club and its coach, to be immediate. There was an ultimatum, now or never, also giving this message to the player himself. You cannot judge Dorgu, you are 20 years old and Manchester United comes to you with an offer like that. The combination of these factors led us to think that we would have gone from being consistent to being stupidly obstinate."