>using cookies to track users based on information that their browsers willingly provide.
Browsers do not "willingly provide" anything. Code is written to trigger functionality. You're ascribing motivation where there is none. Developers willingly write that code.
>If this is considered "theft", then copying anything without removing the original would be theft, which would be a huge problem for anyone advocating for free file sharing or "piracy".
Non-sequitur. Just because the API is there, does not mandate it's use. Free file sharing or even "piracy" can still happen without cognitive dissonance. It isn't the copying that is the problem, but rather the storing, caching, processing and monetization that taken together create a surveillance apparatus that is the problem. The connection to piracy, while undoubtedly seductive, fails to pass muster, because ultimately, entertainment wants to reach audience, and reap value, even if only in brand recognition.
Everyone else does not. Advertising fails to realize, the world is not full of brands looking to be recognized.