Haskell is what happens when you take the idea of pure functions (i.e. no side effects) _really_ seriously, and try to create a programming language that works in that world (modulo mechanisms for doing the side effects you _need_ such as I/O).

It turns out that when you do that, all sorts of stuff that simply doesn't fly in other languages "just works", particularly around representing things using structures otherwise rarely seen outside of mathematical logic and category theory. This is all very powerful and elegant, but it means the landscape is unfamiliar, confusing, and intimidating to programmers who don't have that background or the inclination to learn about it.

Hence all the monad tutorials — not because monads are particularly special, but because beginners encounter them quickly due to IO, so they need some sort of explanation (it's like how if you teach a beginning programmer Java, there's loads of ceremony to explain around classes and public and so on just to do "hello world")... whereas you can get away with using haskell for longer without learning about, say, functors and monoids — though it somewhat misses the point of the language if you do so.