According to wiki
"The film includes numerous and frank scenes of nudity and staged sexual intercourse. In one particularly controversial scene, Lena kissed her lover's flaccid _____. In 1969, the film was banned in the Commonwealth of Massachusetts for being pornographic. However, after proceedings in the United States District Court for the District of Massachusetts (Karalexis v. Byrne, 306 F. Supp. 1363 (D. Mass. 1969)), the United States Court of Appeals for the Second Circuit, and the Supreme Court of the United States (Byrne v. Karalexis, 396 U.S. 976 (1969) and 401 U.S. 216 (1971)), the Second Circuit found the movie not to be obscene.[3]"
Pretty lame reason to be banned.