The claim you cite is essentially a statement of preference regarding a matter of naming/categorization/semantics.
Suppose you were to distinguish some subset of the Universe, labeling it "sadness"; what sets of things would belong in that subset?
Some might consider "sadness" to be a subset of "emotion experienced by a human", which seems pretty reasonable.
The things perceived by the sad person, the things enacted by the sad person--these things are hard to cleanly cut/isolate from the experiencing of emotion of sadness.
The persons experience of sadness is definitely the center of "sadness", but I could imagine expanding "sadness" to include also the inputs and the outputs of that moment, e.g. a sad story. If there were no people left to experience the Adagio, the Adagio would be what was left of the people; I feel comfortable considering it a part of that "sadness"-branch of the human event.
If we find some thing A not really related to "sadness", I can still call thing B as "sadness"
If you consider soul, will, life to be attributes only of humans, you are distinguishing us to be super special. Is my reading a text that changes the way I cycle/move through spacetime so innately different from the collision of two masses? If we allow soul, will, life to apply to the other things that move, we can find the parallels that show humans as an emergent part of nature, whose behavior fits the general scheme of things.
If I am conscious of a flashing light when I register it in my mind, my mind/brain responding to it some regular way, then is not a rock conscious of the earth when it accelerates towards it? Maybe the rock isn't conscious of its own consciousness of the Earth, but it's definitely conscious of the Earth.
Consciousness has connotations of the complexity of human thought, but the crux of it is interaction/cause-effect/perception-action.
I'm pretty sure humans are made of the same stuff as everything else, stuff that we perceive patterns in, but that ultimately transcends our interpretation of it.