What was the rumored reason The Manchurian Candidate was shelved for 11 years?

According to rumor, Sinatra removed the film from distribution after the John F. Kennedy assassination on November 22, 1963. Michael Schlesinger, who was responsible for the film's 1988 reissue by MGM/UA, denies the rumor. According to him, the film's apparent withdrawal was not due to the assassination, but due to lack of public interest in 1963. The film became the premiere offering of The CBS Thursday Night Movie on the evening of September 16, 1965, and was rerun in April 1974 on NBC Saturday Night at the Movies. Sinatra's representatives acquired rights to the film in 1972, after the initial contract with United Artists expired. After a successful showing at the New York Film Festival in 1987, renewed public interest in the film, the studio reacquired the rights and the movie again became available for theater and video releases.