Another reason why we would never date Marilyn Manson (even though the fact that he's Marilyn Manson is reason enough): he's no gentleman! Spies for Page Six spotted the Goth rocker and his GF, Evan Rachel Wood at JFK airport on Friday morning. But Marilyn didn't even help carry Evan's bags! "She was really weighed down with carry-on luggage, while he breezed right through security carrying nothing," the source says. Wow -- that Evan is one lucky girl…