Earlier quoted context omitted.
No, AnimalMuppet is correct. We are unable to value the survival of mankind as objectively good, as we have no empirical evidence to do so (more accurately: we cannot infer an Ought from an Is). See this for more on why: http://liamk.org/is-love-real/ Our options are Nihilism/Zen/Absurdity or Theism. And if the former is true, it doesn't matter if we hold the latter. As CS Lewis put it, if the Theists are wrong after…
Zen is not nihilism (unless you're bandying about the word in a way that has nothing to do with the actual practice of Zen)
All of the practices done before this (meditation, compassion, tantra, etc) are--as in other branches of Hindu and Dharmic faiths--understood to be merely optional "yogas" or activities to fill the time and enjoy oneself in a Nihilistic world.