Then use an accurate legal term for it, "copyright infringement", or a pejorative that both supporters and detractors agree on, e.g. "piracy"

It is an infringement on one's right to control the reproduction and distribution of their intellectual property.

This right is enforced by the authority that grants it. Viewing, listening, or otherwise 'consuming' this IP is not and cannot be an infringement on these rights. Those who provide are responsible.

If a country does not grant or enforce this right (or on behalf of others) then there is no infringment possible in that jurisdiction. cf. China or Russia.

Moral arguments beyond that are your own and should be clearly segregated from the law. Murder is, almost universally, both criminal and wrong. "Piracy" requires more attention to detail in order to have productive conversations.

When you "steal" a secret, it's not longer a secret. When you "steal" credit, the original thinker no longer gets credit. In both cases, the thing itself was destroyed: in the former, the secret is no longer a secret at all and in the latter the boss will no longer be considered the mastermind behind the idea. When you "pirate" something the original copy remains and the creator retains it and the rights to sell copies of it and will still benefit from selling copies. It's not theft.