this is the equivalent of making a movie about a succubus and calling it SUCC

It’s actually slightly worse than that, because “chupa” isn’t just the verb “suck” – that would be “chupar”. “Chupa” is a verb inflection that reads one of two ways: when paired with a subject, it’s indicative (i.e., it describes an action being performed by its subject; hence, “chupacabra” = “goat-sucker”), but without an explicit subject, it becomes imperative. This film’s title is commanding you to suck.