If you believe that Microsoft is stealing Recall data behind its users' backs do you also believe Microsoft is stealing any or all of the files stored on Windows devices belonging to billions of personal and business users? If Microsoft isn't doing that could it be because that would be suicidal from a business perspective?
I don't believe they are proactively stealing user files, but they absolutely pit in backdoors for the NSA and other western intelligence agencies to exploit at will (and I'm sure non-western agencies do it too any time they can discover them).