Yeah it is impossible, mental illness doesn't just go away. It's a fundamental difference in the physiology of their brain.You do not "know"; you assume. The Joker is sick in the head, and he probably won't just wake up well, but it's not impossible.
If that was true he'd go to prison instead of an asylum for the criminally insane. They send him to Arkham because he can't be saved, only contained.Once again, YOU do not condemn anyone. The Joker does. He is not a disease, he is not a wild animal; he is a sentient human being and remains 100% responsible for his own actions at all times.
I'm willing to agree to this. Duv may very well turn out to be more redeemable than I expected, and if she does mend her ways I'll be the first to come on here and admit I was wrong about her. If she kills Fox, well, I'll just say "Called it."That much is agreed. But we don't know that Duv is anywhere near as irredeemable as the Joker - though we also don't know that Saves is as much an idealist as Batman.