The Rossoneri were leading 2-1 when Alessandro Rosina's effort ricocheted off Kakha Kaladze's thigh and on to his arm for a penalty. Rosina stepped up to convert the spotkick.
Carletto said: "I don't want to comment on the referee, I just want to say that the rules we went over with the officials in the summer are that when the ball takes a deflection off another part of the body first, then it cannot be considered a voluntary handling offence."
He continued: "We are accustomed to playing in a very attacking way, although we could have been more compact once we took the lead and given Torino less chance to pressure us.
"We still had plenty of opportunities to go 3-1 up, but the only real fault was allowing Toro to pin us back."
The costly late equaliser means Milan have drawn their last two away games after taking the lead.
"I think we are playing good football right now by using our characteristics of possession and close-passing. What we are lacking is the ability to win games that we have played well. It happened at Lecce and again here, so we've got to learn how to control the tempo more when we are in the lead.
"It became end-to-end stuff and the game was too open considering the scoreline and it wasn't ideal for us to keep giving Torino so many counter-attacks."