I think everything talked about here is sci-fi, but which sub-genre seems to be the debate. I'm especially puzzled by Fury Road as there really is no technology or fantasy element to it. It's the post apocalypse and people are using primitive means to fight for precious resources.
Is that enough to be sci-fi? Are stories like The Road or Book of Eli also Sci-Fi because they are post apocalypse? I can see zombie apocalypse being sci-fi because, well zombies are science based and/or fantasy. What are the base requirements for sci-fi?
Classically, post-apocalyse stories are assumed to be sci-fi, just environmental or social sci-fi (or both). Not all science fiction is technological.