The Star Plus version of Mahabharat shows Ashwatthama speaking loudly against Draupadi. What exactly happened in Kuru Sabha? When Draupadi was forcefully brought into the Kurusabha by Dussashan, Vikarna stood up and spoke against it. It was Karna who stopped Vikarna calling him an idiot. It was Karna who referred to Draupadi as prostitute and asked Dussashan to disrobe her.
Only people speaking during this unfortunate incident were Kuru family members since it was their conflict. The only outsider going out of his way and speaking the loudest that too to humiliate a woman, that too the daughter-in-law of the Kuru clan was Karna. It looks like this dialog from Karna was wrongly attributed to Ashwatthama in Mahabharat TV serial to whitewash Karna at the expense of Ashwatthama.