Here's their concern, as voiced by Mr. Boehner:
"This provision may start us down a treacherous path toward government-encouraged euthanasia if enacted into law."
"Of course, the obese aren't the only troublesome bunch. The elderly are also wasting a lot of our hard earned money with their stupid "last six months" end-of-life care. Eliminating this waste is almost entirely the concern of men under 45 or 50, and women under 25. On the other hand, that describes a lot of the healthcare bureaucracy, especially in public health."
"Once the government gets into the business of providing our health care, the government gets into the business of deciding whose life matters, and how much."