I'm closer to the middle position. An alien watching Earth would not be making value judgements. It would be observing geological change. Moralistic value judgements like "we are destroying the Earth" are anthropocentric, even when they are self-condemnatory. Species self-hatred is historically pretty big with humans and it hasn't stopped us from doing what we're doing. If anything it contributes. Aggressive self-criticism is part of the psychology of an aggressive creature. When we look in the mirror we do so with forward facing eyes.
Don't get me wrong... I think it would be a very good thing if we could stop pumping CO2 into the atmosphere so much. I'm less concerned with the Earth than I am with presently-living and soon-to-be-living human beings. As George Carlin said: "Stop talking about saving the Earth! The Earth will be fine! We're fXXked!"
The reason I've "stopped worrying and learned to love the Anthropocene" is that I see dramatic short term cuts to CO2 emissions as a political impossibility. The best strategy is probably to plan for CO2-driven climate change as a certainty, but also to explore potential geo-engineering approaches. It's possible that we could at least blunt the impact by pulling some CO2 from the air using phytoplankton, desert irrigation, etc. I like the ocean phytoplankton ideas because this would pull CO2 out of the ocean and ocean acidification is potentially worse than climate change.
Developed nations actually have cut CO2 emissions a bit on a per-capita and per-dollar-GDP basis (e.g. USA carbon emissions peaked around 2000 I think), but the problem is that there are billions of people in the world climbing out of poverty and CO2-emitting power sources are still by far the cheapest and easiest energy sources to deploy. This is doubly true for developing nations that don't have the expertise to do nuclear or large scale renewable energy. "Burn crap, boil water, make wheel spin" is pretty simple, old, commodity tech.
The problem is both social and game-theoretic. Game-theoretically global CO2 emission cuts would require an all-cooperate scenario that seems unlikely given the massive economic benefit of defecting. The social problem comes when rich developed nations try to finger-wag at developing nations for emitting more CO2. The response is along the lines of "screw you, we're poor, fXXk off." It comes off sounding hypocritical and elitist because it sort of is... we got where we are by burning a lot of fossil fuel, so who are we to tell Asians or Africans they can't do the same thing? The recent election in Brazil was in part a rejection of environmental restrictions in favor of populist growth policies.
Now toss in the fact that the world is presently going through its globalization trough of disillusionment. Nationalism is rising everywhere. This makes all-cooperate game theoretic scenarios even more hopeless.
The only -- and I mean the only -- hope is that we will develop a very low or zero carbon energy source that is cheaper than coal and gas on a levelized 24-hour basis and that can be deployed just about as easily. I think we'll probably get there eventually, but I doubt Mr. Fusion will arrive in time to keep CO2 under 600-800ppm at a minimum. I wouldn't be surprised at all if it hits 1000ppm.
Africa today is where China was in the 90s... brace yourself for another billion people industrializing and modernizing. Better start researching geo-engineering and preparing to move Miami. I do like to look at the plus side too though. I'm looking forward to more African cultural exports.