The operators don't work as well as they used to, and even when using them lots of results are still left out or are not an exact match. The combination of the SEO arms race and Google's algorithms to filter "bad" information make it nearly impossible to find some things. Sometimes you are looking for that "bad" piece of info as a counter example rather than a source of truth, and don't need google's patronizing filtering, so would prefer exact string matches. But apparently they know better than you.