I'd say we should be fundamentalists, only not religious (or ideological in general). And no, we really cannot "justify the myriad games and delusions" you talk about. Exactly because "we're on our own as species" and there's no reason to "glorify what's natural."

Personally, I would go as far as to say that there is no reason to glorify what is. After all, if there ever was not, there would be no "how would it be like." Yet, one can still appreciate the apparent (self-evident) design.

I mean, it does not matter how you refer to that which humans also call "God." The fact is that, whatever we are, we obviously are. It may be only a human limitation, but we cannot (rationally) go past non-existence. Furthermore, we can realize the spatiotemporal uniformity of consciousness. That is, first person subjective perspective.

I'd say that that is as far as human can go. Still, it already puts life firmly in the domain of "experience generator" (or mirror, if you will). And it really does not matter whether it's by intention or by chance (not even that the domain itself may be just a human construct with no "objective" ground).

As of today, there is no better explanation for all those observations than "God" as "I am", that is, absolute existence/consciousness. Personal, but not a deity. Still, with all "its" omni-adjectives and stuff. Preposterous? Maybe. But even if we are "meaningless and inconsequential in the big picture," -- which humans basically are -- life's already doing what it does.