Hmm, I wouldn't consider a lot of those to be post-rock. That's extending the genre a bit too much. Although the name itself conveys a range of meanings, I think the understood implication, at least from what I've seen, is that bands like MONO, Explosions in the Sky and so on are post-rock while Eluvium, Hammock, Stars of the Lid ect. are ambient, The Album Leaf/Mum have a sort of IDM/ambient sound and so on. Those are a lot of good, less conventional bands you've listed but I don't think they're post-rock.
Especially not BMSR. That one is off the mark to be sure.