It’s hard to decipher the AWS Data Privacy policy:
https://aws.amazon.com/compliance/data-privacy-faq/
In section Who Owns Customer Content, it’s implied that AWS doesn’t access customers’ data:
“As a customer, you maintain ownership of your content, and you select which AWS services can process, store, and host your content. We do not access or use your content for any purpose without your agreement. We never use customer content or derive information from it for marketing or advertising.”
Here, the statement is we don’t access customer’s data without customer’s agreement. But customers do agree with ToS in which different statements might be included.
In another place it’s mentioned, if governments request, AWS will comply. Considering that governments obviously request access from cloud providers, and obviously require them not to disclose the backdoor, I came to the conclusion that governments have unconditional access to data held in data centers of companies such as Amazon, Google and Microsoft.
As for non-government access, there are claims that Amazon uses data or metadata to launch competing products. If I recall correctly, AWS may collect some data presumably to maintain and secure the platform and fight abuse. The counter argument is that, AWS will not risk a profitable business; but AWS is too big to be easily impacted and might act on good opportunities.
It would be great if people working in AWS or similar platforms could chime in.