In the course of “Bad Santa 2,” Billy Bob Thornton’s title character — a dissolute petty criminal who uses his Santa costume to rip off an unsuspecting charity — ogles a breast-feeding mother, makes fun of “retards,” proudly declares that he’s “politically incorrect” and continually refers to women by anatomical epithets. Nasty, leering, brimming with resentment and greed, “Bad Santa 2” revels in the same antisocial vulgarity that made the original such a hit in 2003.