Well it's obviously because fatshaming doctors are on par with Nazi scientists running experiments on their starving Jewish subjects. For the record, the work Nazi scientists did actually holds up to rigorous quality standards equivalent to any other mainstream research at the time. The logic used by the researchers was that the prisoners were going to die anyway, either by starvation, gas chamber, or immolation, so the trials run were no worse a death. In fact some of the research such as the Dachau hypothermia trials make up most of even our modern understanding as to what happens to the human body during hypothermia. In fact most of the techniques for reviving hypothermic patients were developed in those studies. The work they did was hideously unethical, bit it was "good science".