I'm at a loss to understand why people keep using the words "sell data" in this way. It's a weird way to use the word and inconsistent with how it's used in other situations.

Would you also say a pizza delivery driver sells their car? It's a resource that they use while providing a service but they retain possession of the car. Most people wouldn't describe that with the word "sell", so why does the definition shift when it comes to user data?