Some people have a misconception about about the POV of the movie. The POV is from his lover's perspective and it shows how he charmed her, including the other women he had in contact with and basically the media in the 70s. I, as the viewer have admittedly yet disturbingly has been charmed by Zac Efron's outstanding acting. There were moments where I rooted for Ted Bundy and I had to remind myself that he's a crazy, evil dude.
The movie doesn't delve into that typical hack-and-slash serial killer movie stereotype, but it shows us how manipulative and charming these psychopaths could be.
I guess why some people did not like it because they wanted the murders to be shown. But I like how this movie portrays a somewhat different angle of the story. It definitely sets itself apart from other movies of the same genre.