Ehhhh...
I think that takes it a bit too far. The first paragraph states "Unique geographical formations". Oases on Athas are pretty unique no matter how many of them there are because of how rare they are compared to everything else.
But "Every Rock Formation" would mean that you couldn't walk 100ft without passing a pile of rocks with it's own druid protecting it. Or, at least, having enough of a spirit that a druid -could- protect it.
And considering that Athasian Druids don't just protect their feature, but also the surrounding region with an ever-widening radius based on their level, I think the more appropriate interpretation is that the spirits are tied to the Unique ones, but those spirits look over the whole area and work with, or through depending on perspective, druids to tend them.
(I wrote this post hours ago but the site went down so here it is, belatedly)