I took it that the point by Jesse was about how one should frame these issues, not that one should assume a high parity of value between human and nonhuman animals or whatever. The idea is only that these value judgements are properly subject rational argument and should be framed as if they are.
An aside: meta-ethics entered the discussion a unhelpfully here and below. It can be true that one ought to value future generations/nonhuman animals a certain way on a number of anti-realist views (subjectivism, versions of non-cognitivism). Further, it's reasonable to hold that one can rationally argue over moral propositions, even if every moral proposition is false (error theory), in the same way that one can rationally argue over an aesthetic proposition, even if every aesthetic proposition is false. One can still appeal to reasons for seeing or believing a given way in either case. Of course, one will understand those reasons differently than the realist but the upshot is that the 'first-order' practice is left untouched. On the plausible moral anti-realist theories our first-order moral practices will remain largely untouched, in the same way, that on most normative anti-realist theories, concerning ideas like 'one ought to believe that x', 'one ought to do x', our relevant first-order practices will remain largely untouched.