Everything should be measured to the extent to which it is practiced. If someone is sadlife to the point that they're boning their hug pillow and don't even act like real women exist, yeah I would say that is a lifestyle problem akin to insanity.
Furries are pretty extreme, but hey I'm pretty sure not all of them want to fuck a goat or animal. It's just a very, very, very, very strange fantasy.
Moderation should be practiced in every aspect of life.