You’re saying that Recital 43’s citation of “performance of a contract” refers to merely the performance of the provider — the good or service handed off by the provider to the customer. (It’s the sandwich in our example from earlier.) It does NOT also include whatever good the user provides to the service provider as their side of the contract.
So if a service provider says “You need to give me data in order for me to serve you targeted ads, and this is payment for the free service,” the user could not “freely consent” to providing that data, because it is a condition that is not necessary to provide the free service.
Okay, now another question: If the data given by the sandwich eater to get his free sandwich isn’t “freely given consent,” does that matter? Consent was never the legal basis under which the data was handed over in the first place; it was contractual fulfillment, which is a valid legal basis for processing personal data.
What am I missing?
Edit: I do remember the citation you gave earlier from ICO saying that contractual obligation is not a legal basis in the case where it has nothing to do with the performance of services on the part of the provider. I reviewed their site again, looking for a citation for why this is, but they don’t say. I assume they’re pulling that from recital 43, but again — that would seem to me to be a misreading of 43. That only means that the user didn’t freely consent to give that data. But that doesn’t matter because their data is not being processed under the legal basis of consent.