Belgium, the new murder capital of the world. OK, perhaps that's a bit hyperbolic -- but the point is that they're exterminating people for a variety of reasons -- some by choice, others because they are as Hitler the Nazi's called them, Unnütze Esser – (lit. "useless eaters" or "useless mouths")".
As a libertarians, I happen to be for euthanasia. But that doesn't mean I think there shouldn't be any controls on it. And the mental ill or non-responsive (vegetative) can't give consent, so presuming it is not euthanasia it's extermination.