This reminds me of a thread on GoodReads where someone wanted to agree a definition of "Hard SciFi" so that he would know he wasn't wasting his time on books he wouldn't enjoy. He didn't quite phrase it like that of course.
ISTM it's all about trying to get the rest of the world to do your first-level filtering for you based on a label. As many people have said even if you agree on the principle the results will still be subjective. Plus you're basically being lazy - if you want to read only good books you're going to have to do your own research.