AWS has a lot of employees. Many of them don't know AWS very well.
It use to be the case if you were interviewing for an SDE position, you were specifically told not to mention specific AWS services in the system design rounds and speak of generic technologies.
At the same time, I've had two separate Apple SREs in the last 5 years tell me that I should never trust their cloud services.
If you can't see it and can't control it yourself, then you accept these things silently.
My distrust for this goes as far as the only thing actually being subcontracted out for me is Fastmail, DNS and domains and the mail is backed up hourly.