I am sure there are good non aerospace parts, and ones that are engineered to a specific application that could be better than a random aerospace bolt in that application, but that statement is untrue.
Not quite, the company that makes the statement you referenced has a 3 letter acronym which they are commonly referred to by. For years, myself and others I have talked to in the aerospace industry about that statement have been irritated by that claim. It is stated and unchallenged. They make great products, don't get me wrong. But to say "far superior" is false.