AWS are not looking at customers data as it would be professional suicide.
This is why it comes down to trusting Amazon. Essentially the question is "Do you trust Amazon not to do something that would be 'professional suicide', like accessing a rival company's AWS data, enough to risk giving them your data?" If you're running an online retailer that's a competitor to Amazon you should probably fall on the side of caution because companies do stupid shit all the time.
Amazon's the scary-looking flea market on the wrong side of town with the barbed wire on the roof and a couple tough-looking guys conspicuously hanging out out front, with half the stalls full of stuff that definitely "fell off the back of the truck" and the rest selling fake Rolexes and shit.
Doing that at scale doesn't make them more trustworthy. Or it shouldn't. Then again I guess if you're a super-creepy stalker at large enough scale then you're Facebook or Google and instead of getting probation and a restraining order you get billions of dollars, so maybe it does work that way.
This is why it comes down to trusting Amazon. Essentially the question is "Do you trust Amazon not to do something that would be 'professional suicide', like accessing a rival company's AWS data, enough to risk giving them your data?" If you're running an online retailer that's a competitor to Amazon you should probably fall on the side of caution because companies do stupid shit all the time.