Why does Holden think of children and adults differently?

Holden thinks that anyone that has been exposed to the bad in the world is no longer innocent. He believes that as soon as you are no longer innocent that you are a phony and Holden despises phonies. Adults are not considered innocent to Holden, excluding the nuns he met in the diner, they are all trying to impress people with their money, looks, or knowledge. Children don't care about that, they want some one who will be their friend, not try to impress them with their superior knowledge. Children are innocent, and adults aren't. What makes Holden depressed is that the older people write bad things on public places and try to take away children's innocence. Holden wants to protect the children from the phonies, in an effort to keep them innocent.