Human beings are "just animals." Our lives and feelings are "just atoms." Our brains are "just three pounds of fat." These are all examples of a rhetorical and aesthetic move I don't know the name for, and I think it's a critical part of the existential malaise in the West. For now I'll call it the aesthetic fall.
Much of religious thought seems to follow a kind of dualism, where a higher spiritual essence is surrounded by a lower mundane world. As metaphor, some version of this idea extends to the divine (God among inert matter), the philosophical (free will among mechanistic atoms), the political (empire among benighted colonies), the natural (humans among rocks and dead matter), the biological (humans among dumb animals), the social (the civilized among barbarians), and the economic (agents among raw materials). It's part of our language (e.g. "acting like animals") and part of our deep culture.
The trouble is what happens if belief in the dualism collapses. From within the metaphor, a world without God is barren and nihilistic, and a human without free will is a mindless automaton. That's why I call this an aesthetic fall, in analogy to the Biblical fall that led to exile from Eden. Naturally, this aesthetic fall is disturbing and traumatic.
I wonder: why don't more people move in the opposite direction? If humans and animals are not separate, why don't we raise our respect and affection for animals? If we arise from the movements of atoms, why don't we honor and glorify physical law? If someone loses a sense of transcendent meaning, why not attend to the abundant meaning in everyday life?
I don't know. My guess is that moving in the opposite direction deeply challenges the foundational assumptions of our entire civilization. But more fundamentally, it may just be our culture's deep discomfort with nonduality and interdependence.
Any animist or mystical tradition is almost certainly spared these problems, though they certainly have problems of their own.