I don't think anyone ever said that a defensiveless person of any age (whether vegatiative or not) is not human. I think you're reading a bit far into that. I believe what is being said is that when someone is in a vegatative state, no longer able fend for themselves, with little to no brain activity, being kept alive only by a feeding tube, has no sence of what is going on or who there are, with no chance of recovery, etc. there really isn't a point to keeping them alive, or to say, keeping them alive is of no benefit to them. Therefore an executive decision must be made by someone close to the person on what should be done. Someone who is capible of making a decision of such a high magnitude. Most usually, a spouse, parent, or other close family member.
H-D