Earlier quoted context omitted.
A cameraman's salary is paid by the movie's budget, which is effectively a loan against the projected future earnings of a film. Sure the cameraman already got paid for the film you just pirated, but if said film doesn't earn enough then the studio will decide to make fewer films or go bankrupt, either of which could cost the cameraman their job and significantly reduce future earning potential.
But if the movie wasn't worth any money to said person in the first place, then maybe it isn't such a big loss. Maybe some just do not value cinema entertainment very much even though they may watch a movie.
Not to say those changes aren't currently necessary, only that if everyone chose to pirate rather than pay then all of Hollywood would likely just shut down rather than keep throwing $100+m AAA blockbusters into a financial abyss.