In fact, as soon someone feels the need to defend aesthetics in the first place, I'm starting to feel twitchy - for the same reason you don't want to discuss the quality of light with a blind person (not that I deny any blind person the right to know how I experience it).
I think a lot of commenters are right on point, when they argue that none of "retro", low budget, or indie imply shabby graphics. Just as many commenters completely miss the point about "shabby" graphics. Reduced or no graphics at all are not "shabby". Obviously you will have a hard time criticizing the aesthetics of text-based adventures (font-choice, spacing and layout maybe?). Also, just moving from retro to contemporary you won't automatically get "great looks", right? Thus can we finally remove the whole retro aspect from the line of argument?
If you produce art (we do consider game graphics to be some kind of art, right?), and you are criticized for the aesthetics, make of it what you wish. Defending it won't increase your sales. Let the success of the game speak for itself.
And if you cannot understand what people mean when they criticize you, ask them (or others) what could be wrong and how to improve.