The biggest fallacy in today's photography is that a photographer needs to be an expert on everything, from shooting to post-processing, the reality is that while anyone can learn the basic shooting and what to point the camera at, very few actually learn how to process an image 'correctly', and by correctly I mean, at least on the same level as in-camera jpgs.
The Fuji jpgs are a perfect solution for someone who just wants to shoot and not worry about RAW processing. RAW processing is not for everyone.
Ken Rockwell might not be a wise person but when he says shoot jpg, it does make sense because 99% of photographers cannot produce jpgs that could match what their camera's jpg engine can dish out.
If you think the image qualty of fuji x jpgs are no good then, you need to rule out all the issues from your side, because there is a general consensus that fuji jpgs are some of the best if not the best out there among other camera makers.