This is false. iCloud data doesn't contain phone call contents or iMessage data contents. Yes they gave access to metadata, but this is China where privacy basically doesn't exist, not a western country.
The Chinese government access is _not_ limited to metadata.
https://www.reuters.com/article/us-china-apple-icloud-insigh...
Literally the first paragraph of both of bduerst's links suggest otherwise.
Also, I don't know if you've used iCloud on multiple devices before, but it very much contains iMessage data contents.