Why do questions of mine keep getting removed?

Some of my questions (most recently about Macbeth) have been removed. There is nothing inappropriate about them and I am not using them illegally or breaking any of the guidelines. Some of them have comments on them and are still removed. Admittedly some of them are about homework and they are removed, however I do not believe that this is against any rules/guidelines and even if they are, some are not even about homework and get removed