[Ontology] Donald Hoffman’s denial of materialism What the observer brings to experience is a perspective, a point of view, only within which any statement about what is real or what exists is meaningful. Realism forgets the subject and seeks only explanations and fundamental causes which are inherent in the objective domain. But that is impossible, as the very source of that order is the mind of the observer (that's more or less straight out of Schopenhauer). — Wayfarer
And like all idealism his philosophy is saturated with what he is trying to ground through subjectivity: the objective world, language, and society. When philosophers talk about the “I”, they presuppose the “we”, because they do not mean a single empirical subject but the universal form of subjectivity, an idea that assumes its instantiation in a plurality of individuals, i.e., society. When you say “the observer”, who are you talking about? I think you’re talking not only about yourself but about lots of other actual people. Or rather, you secretly or unknowingly abstract away from lots of other actual subjects to the pure form of subjectivity.
That is to say, idealism is parasitic on the real. Both idealists and realists begin with the objective world, that which is not encompassed by the mind, but idealists don’t realize it.
You say “only within which [a point of view] any statement about what is real or what exists is meaningful”, and I can equally say that only within a community of speakers is any such statement meaningful, and further, only within such a community does your observer even exist.