The show is really funny, but just like most American shows, the initial episodes are fine, but as it goes on the filthier it gets. questioning all morality and respect between husband and wife and children and parents.
A character like Peter should be discouraged not made a show out of it!
Again just like most American shows and movies, it tries to convey certain messages, to bring down humanity I feel. There are certain evil objectives behind these, otherwise a comedy can both be clean and funny.