By STEPHEN HOLDEN ecause Menno Meyjes's film "Max" presents a humanized portrait of the young Adolf Hitler as a desperately ambitious young painter, it has been prejudged in some quarters as an inappropriately sympathetic apologia for one of history's monsters. But as the film observes the edgy relationship of Hitler (Noah Taylor) and Max Rothman (John Cusack), the warmly solicitous (and fictional) German-Jewish art dealer who advises him, it presents a fascinating and psychologically credible interpretation of events that may have been crucial to that monster's formation.The movie has the temerity to imply that had Hitler found a patron, his...