Well, man and woman are designed simliar, they are EXTREMELY different in many ways, and each man is different from other
men. Some
men, in a sexual sense, are attracted to breasts more than buttocks, but some find breasts obselete and just want buttocks, and some just want the vagina and nothing else. To answer your question, men are tempted because of the arousal, and because of the general media's view on breasts, it's somewhat of a "shock value" thrill.