If spirituality isn't about spirits, can I also say that oceanography isn't about oceans? Come on now ...
If we take a cultural historic and etymological view on the topic, it''s not that difficult to understand why we now have many millions of naturalistic mystics and spiritual naturalists in our contemporary world -- that is, folks who reject a supernaturalist approach to "things spiritual".
Note that the Online Etymological Dictionary says of spirit that it is "of or pertaining to breath, breathing, wind, or air; pertaining to spirit...."
http://www.etymonline.com/index.php?allowed_in_frame=0&search=spirit&searchmode=none
Here are some words from David Abram on the topic of breath and air...:
"After all, mind is a quintessentially quicksilver phenomenon, impossible to isolate and pin down. As soon as we try to ponder the character of awareness, we discover that it’s already escaped us — for it is really the pondering that we’re after, rather than the thing pondered. We find ourselves unable to get any distance from awareness, in order to examine it objectively, for wherever we step it is already there. Mind, in this sense, is very much like a medium in which we’re situated, like the ineffable air or atmosphere, from which we are simply unable to extricate ourselves without ceasing to exist. Everything we know or sense of ourselves is conditioned by this atmosphere. We are composed of this curious element, permeated by it, and hence can take no distance from it. (The contemporary word for the mind, psyche, was once the ancient Greek word for wind and breath, much as the word spirit derives from the Latin spiritus, meaning a breath or a gust of wind. Likewise, the modern term atmosphere is cognate with the Sanskrit word for the soul, atman, through their common origin in the older term atmos, which originally signified both air and soul indistinguishably: the atmosphere as the blustering soul of the world.)"
https://orionmagazine.org/article/the-air-aware/
Many people deeply associate all things "spiritual" with supernaturalism, but a very large portion of the population does not. I do not. But while my understanding of nature (a.k.a., the real world, reality, the universe, the cosmos...) is fully naturalistic, and thus consistent with what may be called philosophical modernism, I reject some of the pervasive modernist outlook. I especially reject the notion that because there is no god, no gods, no angels, no "spirits" that the Cosmos is basically devoid of ... what to call it? ... Um... Mystery. Not mystery (lower case m) but Mystery. Not a mystery novel with an answer sought to whodunit? But a radical Something which cannot be named but which can be experienced -- sometimes called "an inconceivable Inwardness" ... Folks have always struggled for words for It. It is not a god. It is Mystery, and when we open to It, It reveals Itself. It isn't even an It. It is not a thing at all -- nothing apart. It is everywhere, allwhen. It is not amenable to naming or defining or explaining. It is Being. It is Wonder. It is Depth. It is none and all of these. Without It, the universe appears to be a lot of dead material stuff, all separate, not Living. With It, the universe is felt to be Alive, Vital, Wonderous, Profound -- and most of all Welcoming, even Loving. One need not believe in It. I certainly do not! I am It, and so are you, and everyone / everything else.
But nothing I said is It. It is not a doctrine. It cannot be grasped or told. Nobody's story about It is complete or final or anywhere near adequate, which is why It is usually spoken of, if at all, in poetry and song.
It is Nature. And that's why I'm not interested in Supernaturalism.