I haven't seen that movie, but I laughed out loud when he flew across the river in that scene. Unlike Christian movies, I find that Chinese Buddhist and martial ones have a great sense of humour.
The scene you're talking about looks like Samuel Johnson's infamous refutation of Berkelely's metaphysical idealism. Berkeley said matter is unreal and only minds and their perceptions exist. Johnson said, "I refute it thus," and he kicked a large rock till his foot rebounded from it.
I don't know if that's the main criticism I deal with in the dialogue, since I was interested more in the moral implications. What motivates Buddhist compassion? I understand egoism and selfishness are eliminated with the loss of ignorance and unenlightened craving. But if nothing is substantial (including the self), and only a series of interdependent events exists (much as David Hume said, a concatenation of events with no necessary connections between them), why does the enlightened Buddhist feel compassion? Isn't that an attachment to the cessation of pain? Isn't empathy a desire the Buddhist should likewise only coldly observe with no attachment to it?
The scene you cite does show an arrogant Buddhist talking about the loss of worldly desires, and he's refuted by some mystical, transcendent gibberish. But there's really no answer except to show the hero acting randomly, like an alien being. But instead he often acts benevolently, not randomly or nihilistically. He saves the girl when he flies across the river and he takes the arrow out of the bird. He seems motivated to help other creatures (even though he's also somewhat antisocial or at least not given to idle small talk, and he hides himself away in a cave for a long time).
As I discuss in the other articles I referenced, my question is what saves the Buddhist from nihilism and thus from inaction or chaotic randomness (or from neo-Daoist social Darwinism)? Meditating in a cave for months is inaction and is contrary to heroic benevolence. So the movie implies there's a conflict between the human and the "alien" behaviours, and I don't see a resolution provided. Anyway, that's the line of argument I think the marquis or perhaps a tantric equivalent of a libertine might pursue.
I also haven't read Hesse, but from what I've read about his interest in social outsiders, we may be on the same wavelength.