I understand.
I am a doctor, and neither I nor any of my colleagues have any particular professional qualifications to bring to bear on this problem.
It is wrong, in an attempt to be "compassionate", to call something a disease which isn't-because it implies that the tools we use to deal with disease may work-and they won't.
Kill 'em, or segregate them for life-but don't call on medicine to do the impossible.
What I am suggesting is very much like your proposal to segregate them for life, only in an institution similar to what used to be called insane asylums. I am not asking the medical profession to offer some kind of cure, because I agree with you that this is not a disease. It would be simply a place to hold them safely away from the rest of us.