I don't see the difference 11b. A person like you describe there (mute, blind, deaf, handicapped etc.) would and should be put to death too, because their lives would be living hell. Conscious and devoid of all social contact or ability to do anything...yikes. *shivers*
Of course, without euthanasia someone like that would have the 'joy' of feeling the pain, thirst and hunger when they're starved to death because of lack of euthanasia.
So 'plant' persons and persons like that are both in the same predicament: they are both inable to do anything anymore. What's the point of living? For another few months, even a year, sure. But for the rest of their lives?
The question if someone still has a point going on living (or in this case, being kept alive) depends from person to person and how severe their problem is. In schiavo and the hypothetical dude's case it's pretty clear-cut, in others it isn't. But I'm not gonna explore the nuances of every single case here.
@judges: again, the point of laws is that they are adapted and changed where necessary. Besides, these judges didn't change the laws as such, they set a precedent by making a different interpretation of them. A case such as Roe vs. Wade did exactly the same thing: they called for a re-interpretation of the original law, not for it to be changed.