It is important to note that doctors are just people who have learned what they have been told through their studies and are free to create their own opinions just like the rest of us. Some have done their own research and built their own hypothesis while others follow the guidance of other doctors they know and respect.
I personally believe that you can achieve a healthy life using either a low carb high fat (LCHF) or a high carb low fat (HCLF) style of eating. It is important to note that the HCLF way of eating has never been proven to be any healthier than LCHF.
The popularity of the LCHF way of eating is snow balling, and there is a reason. It works, it is healthy, and it makes you feel great. It has not yet reached the mainstream acceptance that the HCLF way of eating has, but with support from the LCHF community, it will continue to grow, and more and more healthy people will show that this is a great way to control your weight and feel great.
Here is a video explaining the differences in opinions of doctors and the basics of nutritional ketosis.