Idunno Pan. If living like that is not mentally ill, then what is? Who in their right mind could think that's even in the same universe as "OK"?
Living in amongst your own feces; storing your urine; eating rotten maggot-infested meat; allowing trash and discarded food scraps to accumulate until you're on top of it four/five/six/seven feet deep no matter where you go in your house; living with the stench of dead and decaying animals right next to where you sleep... and then railing against those who want to "take away your things" when they come to help you clean? It doesn't seem to me that such behavior could exist outside of mental illness.
It sure seems to me that each and every one of the people who does this is exhibiting mental illness long before the docs arrive, not to mention the fact that in a majority of the cases, there seems to be a pattern of behavior that - if I were to apply my layman's understanding - would be classified as "clinical" behavior - as in identifiable previously documented traits that offer a reference to some consistency in behavior from one patient to the next.
But whaddoIknow. I'm no mental health doc either.