Have you considered that the only users who access XML files might be a) at work (where you won't get telemetry) or b) techies, who also disable metrics?
You can't just use the metrics of "what do people who don't know how to disable telemtry use?" to make decisions for everyone.
Where's your proof that it is in use sufficient to justify maintaining the functionality? If you have such data, take it to the decision makers. Nobody's going to make decisions based on hypotheticals in the presence of data.
As more than one VP has said at my company: "In God I trust. Everyone else needs data."
By your logic, nobody should take an action unless the data that supports it is flawless. That's not how the world works and would lead to widespread decision paralysis. Most of the world's progress is based on taking calculated risks based on the information you do have, despite imperfections.
You can't just use the metrics of "what do people who don't know how to disable telemtry use?" to make decisions for everyone.