A spiritual realm is synonymous with an immaterial realm, since it is not a material realm. And, immaterial tells us what the realm is not, that it is not composed of matter, but it does not tell us what it is. Accordingly, you are once again begging the question, and arguing nothing at all, since your terms are undefined.
Moreover, the notion of an “immaterial realm” entails a contradiction and cannot be expressed in positive terms. We cannot imagine an “immaterial realm” because the concept of “matter” is essential to our concept of “realm.” The spiritual realm, you claim, is a “realm”–but it does not occupy space, it does not have dimensions, and it cannot be perceived, measured or detected in any way. And these qualifications render the concept of a “realm” of vacuousness.
Now, I’ve noticted that you have objected here, pointing out that many words–such as “justice” and “consciousness”–do not signify material objects. The referents of these and many other words are immaterial, so why should the atheist complain when the spiritual realm is also said to be immaterial?
While it is true that “justice” and “consciousness” do not designate material beings, you must remember that they do not refer to immaterial beings either. . . . “Justice” is a moral abstraction derived from various aspects of man’s nature and social interactions. “Consciousness” refers to the state of awareness exhibited by particular living organisms. “Justice” and “consciousness” are not material entities, but they depend on matter for their existence. The spiritual realm, on the other hand, does not depend on matter in any way; it exists in its own right as an independent “realm”. In this context, however, “immaterial” is stripped of meaning.
To say that the spiritual realm is immaterial, or nonmatter, is to say that we can have no sensory experience of this realm and that we can never conceive of it. This characteristic, therefore, simply throws you into agnosticism.