When you enter a shop you become a customer, not a human being with feelings. Same goes for those platforms. You enter it and you become a consumer. If you're like it or not.

You enter the shop as a human being, and there's certain (human) rights that should come with that.

We're talking here about the right to get a copy of your own data, the right to be forgotten when you want to leave, the right to be informed about data breaches, and a right to agree to types of data processing.

Your analogy is "you enter a shop and cannot leave again, may be abused, and lose control."

That makes little sense when you think about that. The constitution of your country does not stop at the door of a business. All your constitutional rights as a citizen enter the store with you. You have also human rights granted by international treaties. Nothing stops applying because you enter a shop.

Facebook isn't selling me anything though.

Neither is google