Look. I love Haskell. I usually formulate solutions to programming problems in my head in Haskell before I write code in whatever language I have to deal with. Constructing programs using combinators? Great. Assuming referential transparency everywhere? Great. It's a great language.
But there comes a point in time where you have to project that stuff all away and get down to the brass tacks of what's happening in your system, leaving behind the Platonic heaven you've constructed for yourself. As the patch proves without a doubt, this is very possible to do in Haskell. But sadly, the general ethos of the Haskell community does not bend in that direction. I am a lover of the language, but at the same time a vocal critic of the community in that respect.
Given the amount of effort and mindshare that libraries like Vector, Bytestring and Repa get in the Haskell community, I really don't see where you got your impression. Not everyone cares about performance, sure, but plenty of people do leading to some heavily optimized libraries.
In this day and age, having everyone worry about performance is patently absurd. Most programs don't need to be heavily optimized, so prioritizing programmer efficiency and correctness just makes sense. And Haskell does have the libraries, language features and people to optimize the parts that need optimization!
Why is Haskell different than any other high level language in this regard? All high level languages make compromises between expressivity and performance. If you want to code really close to the metal, C exists and you know where to find it.
But there comes a point in time where you have to project that stuff all away and get down to the brass tacks of what's happening in your system, leaving behind the Platonic heaven you've constructed for yourself. As the patch proves without a doubt, this is very possible to do in Haskell. But sadly, the general ethos of the Haskell community does not bend in that direction. I am a lover of the language, but at the same time a vocal critic of the community in that respect.