"The continuation of humanity is inherently valuable" is not objective. Yes, it is a value that most people hold, but that does not make it an objective truth. At best, that makes it a common axiom.

That you had to qualify "nearly everyone" holds that value itself demonstrates that it is subjective, not objective.

There is no fundamental universal property that makes humanity inherently valuable. Humanity can cease, and the universe will continue on just fine. We can say that's bad, and construct our morals around that axiom, but that doesn't make the axiom objectively true.