The optimal answer, on many Stack Exchange sites, is written by an expert - or, to avoid having to define that word, a person who is very well acquainted with the subject and specific material at hand. They're likely trained in the discipline, and so, all other things equal, they're more likely to be right in their answer. I'd argue that we should actually try to get such literary experts to write such answers, so they aren't simply quoted.
At the same time, just because someone is an expert doesn't mean they're always right, especially if the question deals with something outside their primary area of study. I join Aurora0001 in emphasizing that you should do more than just read the name appended to the quote - or the answer.
All that said, I'd be more inclined to trust the word of a literary critic - whatever that means - over a simple layperson like myself. (Ideally, citations would arise in an answer, no matter who it's written by.) However, just because someone is such an expert won't necessarily make-or-break my voting on a post.