Keep reading, Surya. Later on the Buddha speaks of the contraction of the cosmos and also how it starts up again. He speaks of the re-emergence of beings after they’ve spent a very long time in the realm of streaming radiance. And within the explanation of how beings evolved into ordinary people, he talks of their characteristics being based on principle (not by birth). The first part of the sutta is admittedly un- interesting, but it’s worth your while to continue.  I probably should have titled the post differently. And, yes, I do think that the Buddha is distinguishing himself from the Brahmin caste superiority of his time. Anyone from any caste was welcome to join him, although women had to persistently beg and ultimately got Ananda to successfully plead on their behalf.