If its very difficult to tell what a film or main objective was it trying achieve who is most likely responsible?

The director is most likely responsible if it's very difficult to tell what a film's main objective was or what it was trying to achieve.

The director is the creative leader of a film and is responsible for overseeing all aspects of its production, including the development of the screenplay, the acting, the cinematography, the editing, and the music.

If the film's message or objective is unclear, it's likely because the director did not effectively communicate their vision to the rest of the filmmaking team.