This form of criticism is along the lines of "The Gettysburg Address is just words anyone could write." The important part of creative work is not the potential but actually doing it. There's no such thing as "a design in my head."

Don't get me wrong, I'm not claiming that the logos are cultural artifacts of high calibre. But that what they share with such works is actuality. Their creator can get better in ways that everyone who could but doesn't can't.