Society makes this judgement every day in a thousand different ways. Resources are limited. It's why we don't give 85-year-old's heart/lung transplants - the 30-year-old recipient can use it better/longer. Does that mean we don't give any health care to 85-year-olds? No, and to argue it is so is a slippery slope fallacy. It's why we don't have lights on all 4-way stops even though it's safer than stop signs.

Given that we make these judgements, the problem with your argument is that you paint the GP as some sort of monster for making the judgement and picking a spot on the scale. It's a valid thing to disagree with where he picks on the scale; it is invalid to argue that there should be no scale.