I understand Apple's position on this one. This is essentially a backdoor into all of your data. It is also a very useful feature. The EU regulators are disallowing guardrails without which this backdoor will be used to strip-mine people's personal data. The privacy implications are not legible to most people. If I was more cynical I would suggest that this is being used as an end-run around encryption, since the enc…
It would only be a backdoor if it's implemented as a backdoor. The way Apple Health exchanges data with 3rd-party trackers (Fitbit, Garmin, etc.) is very well built and a good model of how other components in iOS could allow data exchange with very granular permissions. Apple touts the "Private Cloud Compute". If they found a way to share your personal context to process on their cloud in a private and anonymized way…
You don't seem to know how backdoors work.
Oppressive regimes mandate that tech companies pre-install apps to protect people from spam calls, or install specific root certificates so they can intercept your traffic and insert a helpful banner into your browsing session to remind you when to pray.
The EU isn't going to ask Apple to add DataCollectionBackdoor(). They are going to demand that in the spirit of freedom and happiness EU companies must have access to Apple users private data.