He thinks that the movie exploits a horrible tragedy and he wished that it wasn't made. Ironically, he and the victims' families are on the same side regarding this particular issue. Making these people famous only increases the odds of additional offenders. Since the beginning of time, people have been fascinated by the dark side. He's still a sociopath.
Society is never happy.
But if a Berkowitz or someone else then appears to be rehabilitated, people don't want to believe it. So they're damned if they do and damned if they don't. She heard things she shouldn't have and they killed her to silence her. That victim was Donna Lauria. That motive involved a complicated lover's triangle.