I think it's wrong on many levels haha, it's a little misguided at least.
I only looked at a few of the first FAQs but I think I got the general gist of it.
I'm not sure what would be considered 'good health' for the biosphere, or when it has ever been in 'good health'. You can define 'good health' by what is required for our species (or other species) to survive but that's entirely subjective. A good biosphere is whatever biosphere supports the life of the species living in it. I guess there's always the chance that our planet wont manage to revert from a snowball or greenhouse earth and end up like Venus or something, but geology and palaeoclimatology seem to be on our side as our planet just fluctuates between the two extremes with periods of relative niceness in the middle.
We know we can sustain the human species as well as the majority of other extant species on this planet if we play our cards right, seems a bit silly to sacrifice ourselves for every other species considering how long this would take and how pointless it would be.
I have a feeling that people who would only have one or two kids, be concerned about the environment, have above average intelligence, and have the money and life style to support a family are the ones who are more likely to follow VHEMT than people with the opposite attributes. If this was taken seriously by enough people, we'd probably make things worse quicker.
I get that some people may not want to have kids (for me, it depends entirely on my future circumstances) but it seem pretentious to use VHEMT as the reason why. There are a bunch of others things that someone of that mindset could do instead to help conserve our current biosphere.
Below are a few quotes I hand-picked that don't make scientific sense:
We have evolved into a virtual exotic invader of Earth’s biosphere as a whole, incompatible with undomesticated life forms.
Many species, not just apes, exhibit intelligence on a par with us—though we try to skew the criteria for intelligence to make it seem like we’re the smartest
Nothing is either at the 'peak' of their own evolution nor is anything at the 'peak' of evolution in general. The theory that evolution leads towards progress lost most of its support a few decades ago; there's no trend towards progress, complexity, or size.
In a sense, all living things are at the peak of evolution
I guess it's refreshing to see someone so concerned about our impact on the environment but his reasoning doesn't make sense to me from a reductionist perspective. The current biosphere wont be around for that long (in geologic terms) so why bother trying to preserve the current extant species if we do not try and preserve ourselves? Current environmental efforts are focused on preserving the current climate and current extant species, which includes us. If we eradicate ourselves, we have no need to preserve the current conditions because it doesn't matter; those species will become extinct whether we are here or not. But, if we intend to stay here, it is in our interests to preserve the environment as best we can.