By Pat Padua, Special To The Washington Post In Washington, there may be no more loathed profession than that of the lobbyist. The political thriller “Miss Sloane” paints a cynical behind-the-scenes picture of the great lengths to which paid advocates will go to advance a cause. But even if you admire the drive of its title character, Elizabeth Sloane, a sought-after lobbyist played with cool ferocity by Jessica Chastain, you may not admire the means she uses to achieve her goals. The film suggests — gasp!