When you ask me to prove it, you're asking me to reinvent the wheel. You don't seem to understand the difference between dealing directly with an argument and dealing personally or psychologically with the person making the argument. Why else would you have asked outright, "Is there a cosmicism in the abstract independent of humans?"

It's not surprising, then, then you reject the claim that you committed the ad hominem fallacy. To accept that there's such a fallacy, you first have to accept the principles of formal logic and critical thinking. If you're radical enough of a mystic or a theist to reject all of that, of course you'd be inclined to brush off the idea of violating those principles (such as by engaging in a personal attack with words).

I'm not going to go through all of that here. You had a choice between responding to the arguments in the abstract, independent of the personal or psychological issues of motive, and focusing on the latter potential issues. You went "to the man," which is the essence of the ad hominem fallacy. The reason it's a fallacy is that there is indeed a choice to be made there, and impugning the man isn't the same as refuting the argument (except perhaps in a court of law, which has different principles and rules of engagement).

Of course psychological considerations have their place: in psychology. Here we were talking about what's philosophically, objectively true in a much broader sense.

I'm aware you've engaged directly with scientific and philosophical arguments in your writings. Here, though, you dropped the ball. It doesn't matter what motivates cosmicists. Cosmicism could be true, regardless of the character or possible mental problems of cosmicists. Indeed, the truth of cosmicism might cause those very mental problems. And it's the same with theism and theists, which is why the ad hominem is so cheap.