Is it that extreme though? It seems reasonable to assume that our ancestors would have been in and out of ketosis frequently in pre-history, meaning that our physiology should well adapted to this state of being.
I have so many health benefits from ketosis that I'd simply answer who cares?
But there is plenty of quality research these days backing up ketogenic diets (Volek and Phinney work is outstanding, Chris Palmer on the benefits for mental health too, just to name a few) that associating it to fad diets is simply ignorant misinformation.