Couple of people I know are on ketogenic diet (one more than the other), and some others have played with it -- all reporting extremely good results/very excited about how effective this is. So there's no need to "believe in ketosis" -- it's objective reality.
Although joking aside -- yeah I definitely know what you mean, it really does feel almost counter-intuitive, especially after having been bombarded for several decades(!) by the "eating fat is bad" messages from every single angle, from government to health advocates. It's really great to see the good info spreading around more.
Depending on your activity level you don't
have to go completely-ketosis, but again one guy I know has been in that state for a few months now and feeling great.
If you're exercising enough, there's nothing wrong with carbs -- as long as they're not highly-processed/not coming mostly from things like white bread(-related products), pasta(-related products), etc.
Good luck!