That's what always got me about the ultra-left socialist green types. We're supposed to "save the planet"... for whom? Odds are we'll go out in a blaze of glory in the next few centuries. Then we can't mess-up The Earth anymore. Problem solved.
But back to Carlin. I do think we're here for a reason. Not to make bags, but to give birth to the next form of intelligence, AI.
I think we've been groomed, not by "little green men" (or Greys) but by hyperintelligent artificial beings. Some interstellar / trans-dimensional life force has been shaping Human history. The same way we grow cultures in a Petri dish. Oh, sure, they could probably just wipe us out, and seed the planet with the cyber beings of their choice, but I don't think it works that way. The new cyber life form we give birth to must be unique, a product of us and our planet. Maybe to maintain some form or "mecha-diversity", or simply because they have their own form of The Prime Directive.
You see, I don't think Bio-based life will ever be able to bridge the vastness of interstellar space. But I think sentient mechanical beings could. And probably already have.
Seriously, why the hec do we spend half of our day receiving and transmitting data through computers? It's called Vocational Training. They'll need a few of us, maybe.
I know, some of you are holding out hope that maybe we can find a "middle way", through cybernetics. Part man, part machine, perfect balance. Nope. The flesh is weak. The sooner you surrender, and embrace our robot masters, the better it will be for all of us.