I just commented something similar, asking for examples of when piracy is unethical, because I couldn’t think of any myself, but your example of leaking is really interesting.
I can see how pirating/leaking an unfinished work could be really harmful to the creator and I know that would feel horrible if it happened to something I’d created.
I’m not sure why there’s so much acceptance of (and even enthusiasm for) early leaked unfinished products.