They are only harmful if person becomes to drawn to it and has ideas to become a vigilante or try to jump off a balcony. When you get past that it just good movies and comics to entertain yourself with. I don't think anyone takes them other then a work of fiction after a certain age. Even then kids would dress up as them or find a sense of courage of them. What they do with it is up to them and not the fault of the people who created the idols. Superman is a goody to shoes. Batman beats people up. I doubt any kid can beat people up and Superman is perfection that kids can strive for and never achieve. Batman is more deep then Superman. He has more issues to deal with then Superman because Superman is a living God and Batman is only human with a lot of money. Generally kids would like Superman more and an older audience would like Batman.