“Suspiria” is bad. “Suspiria” is a mess. “Suspiria” is a movie set in 1977 Berlin that’s about both a psychotherapist mourning his wife and about an American Mennonite girl who gets admitted into a prestigious dance academy that turns out to run by a coven of witches. “Suspiria” tries to do many things and does none of them well. But this and its other technical problems are the least of its flaws. In fact its greatest flaw — no, its greatest sin — lies in what it tries to seem like it’s saying and what it instead is actually saying.