"Who I'm friends with or not friends with is not your decision!" Padma said, starting to get angry. "If I choose to give someone a second chance, that's my decision. Not yours. Barty is not evil - I have talked to him and I know what's going on with him and I am not going to stop being his friend."
Barty needed someone to see the good in him, to encourage him that he wasn't the old, evil Death Eater anymore. He was someone new, and Padma was determined that the new Barty would have a chance at life.