Nice.
You know, despite your righteous indignation, the issue in this thread comes up pretty frequently. People (MR or not) with recurrent pneumonia will request no further intubation or have it requested for them by their guardians. And children born with severe chromosomal abnormalities will have invasive/life-saving interventions refused by the their parents. A parent faced with a profoundly MR infant will sometimes refuse surgery for TE fistulas, cardiac repair, or other interventions that will undoubtedly result in the child's death. Sometimes this is met with a fight by the physician, other times the doctor will go along with it.
So why are you getting so worked up? Is it DKM's "lack of sensitivity to the subject"? Because I've got news for you, people who have actually functioned in this world frequently do not show the level of reverence you are demanding. If you want to cry with every patient facing a hard situation, feel free. The rest of us utilize callousness to protect our own hearts. Wanna guess who lasts longer in this field, seeing pain and horror every day?
For myself, I see a couple different levels to this discussion. Refusing treatment for a child is not a simple matter, and specifics of each case do come into play. There has to be a judgement made (both by guardians and providers) as to the potential benefit of the intervention versus the pain/invasiveness of the intervention. Refusing intubation or surgery seems to be a little easier that refusing antibiotics or IV hydration. This is probably a good thing.
Physicians who are uncomfortable with a parent's decision always have recourse available. First, they can refuse to perform procedures/treatments if they consider them medically futile. Second, they can seek cover from the hospital ethics committee. Third, they can ask for intervention from the local CPS or equivalent. Fourth, they can attempt to get the hospital's legal department to initiate guardianship of the patient. What they do not have to do, under any circumstances, is provide or withhold care that violates their conscience, although this may mean transfering care to a different provider.