Per the article, the NTHE "movement" are doom sayers, not doom pushers. That is, the NTHE people are people who predict that humanity and most complex life on Earth will be killed off by global warming by 2030 (used to be 2026), through a somewhat convoluted but unavoidable series of consequences of the polar ice cap melting completely (in their theory). There is no indication that the NTHE people want this outcome to happen, it's just the outcome they think is already unavoidable.

Now, the author's position is both more and less nihilistic. The author also seems to think that human extinction is unavoidable, but he thinks the timeline is much more dragged out. He also seems to think that this is actually the preferable outcome at this point, given that global warming is our own fault, and that the only thing we should do is try to make it so that the planet is as well as it can be after we are finally gone.

It reads to me as a prediction, not a desire: if we don't prevent NTHE then NTHE will happen.

It's humans who are doing this to themself and every other species on earth. So it's true.