Then why cant the same argument be applied to Agatha? She didnt need consequences, she needed a good teacher to show her the right way....
So, the difference is trauma. Some people act badly because of the results of trauma, others because they are horrible people. We have no indication that Agatha had suffered trauma, we have an entire episode outlining Wanda's.
Overall, when Agatha hurts people, she comes out satisfied. Agatha shows no signs of caring or empathy for the pain she causes. She at best pays lip service to it in a "I can remove your pain" way, but lies in the process. Wanda feels remorse when she realizes what she's done.