Oh I don't mean to say it detracts, quite the opposite. I think it is because these artists love a childs form the way they do that they are so passionate in creating them. Miyazaki is an amazing artist, that cannot be denied. Even before he was selling out to make hackneyed kids cartoons he created one of the most influential and groundbreaking manga of its time. The man is a master of design and world creation no doubt. The fact he is a lolicon helps that, and so is a positive in my mind. He's pretty famous for saying he wished he had made Naussica's breasts smaller, I think that sums up his interest in design pretty well.
He loves girls, he's said as much. And its his stated reason for always involving them as primary or secondary protags. Theres nothing wrong with that really.