so for example a diet is simply a good idea taken to such an extreme that it now kills people.
for example you start with the idea that High Fructose Corn Syrup is bad ... and you develop this idea further making it more and more extreme until you end up with Keto / Carnivore diet.
then you ostracize anybody from your movement who points out that this diet is deficient in Vitamin C.
you rake in the Cash selling books and giving speeches while your followers who get Scurvy are told something like " you must have cheated and had some carbs, and that's why you got Scurvy - it is because your diet wasn't extreme enough is why it didn't work "
every time i pointed out the diet doesn't work i was told it's because i wasn't extreme enough in applying it, and every time people complained of severe side effects they were told it was temporary and the solution was to go HARDER and LONGER ...
for example Raw Vegans call this "detoxing" ... that's when you feel like crap on their diet but they tell you to keep doing it anyway. there is no actual "detoxing" occurring - in fact there are orders of magnitude more toxins in raw vegan diet than in almost every other diet including SAD ( Standard American Diet ) but the fact that "detoxing" is the opposite of what is happening only makes it better as propaganda.
likewise Carnivores always brag about how fast their wounds heal ... because actually wounds not healing is a sign of Scurvy which you will get by following their advice.
and Urbanists brag about how much they enjoy riding bicycles and preach the importance of never wearing helmets and never obeying any traffic rules and when they get hit by a car while running a red light they say it's all the fault of "Car-Brain" etc ...
it's always about taking any good idea to absurd extreme, ignoring all calls for any kind of common sense, blaming all problems on other side, while claiming the reason your system isn't working is because the application of it isn't extreme enough ...