sure, but the criticism or better put, the commentary on fasting is on how people tend to use/view it for weight loss as if it is something unique about fasting or time restricted eating when all studies that equate for the calories dont see any difference for weight loss and if a person is actually trying to build/maintain muscle it is actually very detrimental/suboptimal...
the keto diet i think was 'invented' as a solution for folk that had issues with epilepsy and/or seizures. to even get to ketosis requires is strictness very few people can maintain in order to get their body to switch over to using keytones...at which point it is less about the fasting/ketosis than actually being able to restrict the caloric intake
true they go waaay left with topics often, they are knowledgeable dudes tho...since i have been checking for their content i mostly listen to the opening clickbait part and the part where they answer listeners's questions, which i find informative...
their point about fasting, especially as it concerns their audience & what they advocate, is just it can be a useful tool for some immediate/temporary goal but as a diet/lifestyle it is not a good approach for building and/or maintaining muscle or weight loss/management...obviously individual results will vary but as general advice it makes sense