Major difference between "we won't support big endian" and calling RISC-V out as stupid for adding optional support.

The academic argument Linus himself made is alone reason enough that big-endian SHOULD be included in the ISA. When you are trying to grasp the fundamentals in class, adding little endian's "partially backward, but partially forward" increases complexity and mistakes without meaningfully increasing knowledge of the course fundamentals.

No zbb support is also a valid use. Very small implementations may want to avoid adding zbb, but still maximize performance. These implementations almost certainly won't be large enough to run Linux and wouldn't be Linus' problem anyway.

While I've found myself almost always agreeing with Linus (even on most of his notably controversial rants), he's simply not correct about this one and has no reason to go past the polite, but firm "Linux has no plans to support a second endianness on RISC-V".