As a data science python dev I'm learning Clojure right now (at home for fun) to build a personal website. I'm actually completely new to web-dev. I suspect if I chose JS I'd be done by now, despite not knowing JS. It's all just sort of the 'same' in a sense. Whereas even loops in clojure really force you to understand what the hell you're doing. It's fun in a challenging way.

My take: Because it is more difficult for most people. I suspect that most peoples' brains don't work as well in that style. Yes, they can learn. But no, it would never be the best fit for them.

For some, FP is actually more natural. To them, it's a revelation and a freedom, and they can't understand why everyone else doesn't also find it to be wonderful.

Well, for many people BASIC with "goto 10" feels natural and easy. Maybe for most of us, if the programs are small. The question is: How do we deal with increasing complexity? FP is an answer, OOP is another (certainly not orthogonal) one. But people learn some traditional imperative OOP language at college and stick to it. They are told "goto considered harmful", but "imperativism considered harmful" did not really make it in their head.