The literary evocation is far more powerful than the word-part "soy". Even so, given soy's ubiquity I suspect that no one would seriously be turned off by it at this point. The name doesn't "essentially mean cannibalism", it refers to a fictional future company that makes the bulk of the worlds' food in the form of Soylent Red and Soylent Yellow. In the movie Soylent introduced a new product Green that you refer to, which means that the only people who are disturbed by the name are those who take things too seriously and also didn't actually watch the movie.