SF stories don't need to be "sciencey". Quite a few have no science whatsoever, as they tell post-apocalyptic stories where what is left of society has regressed to pre-industrial days. Maybe that is also why it is increasingly called "Speculative Fiction" these days - to avoid that confusion.
It's not that "S11 is dystopia and therefore SF". It's that S11 talks about a future world where major changes have meant significant changes for human societies. That makes it SF. It is literally the broad definition of SF.
Personally, I wouldn't say S11 is much of a dystopia, even. Nothing terribly dystopian happens, really, except that they don't have modern comforts like air conditioning (about which they moan a lot in the book 
). Nobody seems to have much trouble meeting their basic needs and staying alive, miraculously, living how they like moping around all day, whining about lost comforts .
Dystopian fiction is a sub-genre of SF, that is a different matter. I said it because people were saying "It's dystopian, not SF" which makes as much sense as "It's a biography, not non-fiction".