The kind of people that will whine about a project someone esle has done are everywhere, and share a common trait - they haven't done or can't do it themselves. A neighbor came over to inspect a deck the wife and I were building. His only comment was, "I really don't like the way you've done those foundation blocks." Later his wife came over to tell use we hadn't done the railing right. Both comments were answered with, "Oh well, that's the way we like it" and then a change of subject. People like that are best handled the way you did. Politely ignore them.