It's interesting that your response, like Sender Spike's, is largely ad hominem. As I suggested in my comment on your Part One, you're not exactly dealing with a fair representation of my views. That's alright because I've written a lot and even I might have trouble summarizing it all.
But as a matter of strategy, I think it might make more sense for you to criticize cosmicism in the abstract rather than to commit the genetic fallacy and reduce cosmicism to a wayward personal upbringing.
Thomas Nagel's "The View from Nowhere" shows us the truer source of this pessimism. It's a case of a clash between subjective and objective perspectives. Normally, we look at the world subjectively, projecting our interests onto everything and presuming our importance in view of our intuitions and prejudices.
Then objectivity comes along, the potential to detach from our personality, to empathize with others and to imagine what the world is really, noumenally like, independent of our interests. It's objectivity itself, in philosophy and as institutionalized in science that's the source of "cosmicism," the latter being a dramatization of our belittlement as a paradoxical side-effect of the vast expansion of our understanding of nature. The more of nature we encompass in our objectivity, the smaller we seem to ourselves.
Subjectivity and objectivity are in dire conflict, for Nagel. Bridging the two has been a major theme of modern philosophy. By contrast, religions tend to prioritize subjectivity at the expense of objectivity. Christians, for example, might interpret objectivity as so much demonic vanity.
In any case, the question you might want to ask is whether this objectivity is just another form of mental or cultural projection. You want to say that atheists tend to be projecting their spoiled childhood or whatever. You could extend this line of criticism by saying that so-called objectivity expresses the sinful impulse to dominate nature. This is the Frankfurt School's line of thought, and I incorporate it with the pragmatic side of my philosophy. See also my talk of "humanization" in "Transhuman Epistemology: Knowledge in the Cosmic Scheme."
In other words, there's a question here about the nature of objectivity that gives rise to cosmicism. Is this an innocent process of personal detachment (or of depersonalization) or a fundamentally sinful and optional one? Can we choose to view the world as primarily physical or mental? Is there a Kierkegaardian leap of faith involved? Are character traits (virtues and vices) responsible for these outlooks? Would pure objectivity amount to a peak state of consciousness or to an uncanny sense of Being's strangeness?
As a side note, the first point of your summary of cosmicism isn't quite right since Lovecraft is famous for using superintelligent aliens as gods in his stories A cosmicist could also adopt a pantheistic framework, according to which natural forces, elements, and regularities are divine.
The crux of cosmicism, in any case, is the clash between objectivity/naturalism and subjectivity or the intuition of our great importance in life. There could even be a theistic form of cosmicism, as long as it's God that crushes our private and anthropocentric hopes and dreams. Or this could be done in pantheistic terms, as nature, deep time, and the colossal scope of evolution will reduce the Anthropocene to ashes in an afterthought.
There are indeed shifts of perspective here. The question is which perspective we should adopt, or whether any is inevitable.
