> If everyone pirated Marvel movies then Marvel would not be able to make $100+M movies and these movies would not exist, which is a contradiction. Therefore piracy violates Kant’s categorical imperative, therefore piracy is unethical.

Here is where your use of the categorical imperative breaks down: creating an economy that prevents Marvel from making movies is not in itself unethical. Undesirable, perhaps, but not unethical.

No one is entitled to have their favorite business model work regardless of whether or not it makes sense in a given economy.