The need for contextualization exists because humans can not free themselves from the good-bad binary. That being said, contextualization is also needed because we are now in a post-disciplinary moment. How long that moment will last is another question.
Because we are in a post-disciplinary time and still are saddled with the evaluative binary, we need contextualization to help us determine where a given work of art/documentation/performance/representation lies on that spectrum. For better or worse, we are no longer saddled (not really but roll with it) with the evaluative binaries of disciplines, which are themselves shorthands for contextualization.