You'd have a hard time justifying the argument that moral frameworks are arbitrary. First, they have complicated internal structures that aren't well understood even today. See, e.g., the various "paradoxes" of modal logics used in ethics. Second, since we're all the same social primate species, moral rules are surprisingly consistent globally. Third, the Romantic and anti-Enlightenment streams that Nietzsche was a part of generally did away with the need to justify claims. This vibe-based approach is a big part of why people like Nietzsche are sometimes viewed more as literary figures than philosophers.
Nietzsche was very strongly in favor of the aristocracy and opposed to democracy. Traditional mass market religion was always something the ruling class saw as beneath them. For a long time the ruling class was the priestly class, so they literally made the rules of religion. That was no longer true in Nietzsche's day, but his views on morality are still influenced by the fact that he's writing motivational works for the ruling class.
It's just not interesting, its not really foundational, it weirdly adopts the value frame of what it rejects, its arrogant, much of it is trivially false.
It's like hearing someone talking about reading Von Mises or Ayn Rand or Myers Briggs types for the first time.
It's like, I'm too old and well informed now to find any of them interesting or of value, maybe they're a developmental phase and are ok if you don't get stuck in them.
Read them sure, but if you're the type of person who believes what they read and can't engage with it critically your better off reading more substantive and true works, like cheaper by the dozen or the boxcar children, or the musicians of brennan or read more interesting, modern, informed work like Wheeler.
Nietzsche was very strongly in favor of the aristocracy and opposed to democracy. Traditional mass market religion was always something the ruling class saw as beneath them. For a long time the ruling class was the priestly class, so they literally made the rules of religion. That was no longer true in Nietzsche's day, but his views on morality are still influenced by the fact that he's writing motivational works for the ruling class.