Completely agree - what I'm wondering is why they are telling their customers that they can verify the data for themselves, when that is entirely pointless: "and using cryptography, you can easily verify that there have been no unintended modifications to your application’s data"
If the digest you provide is found, then you know the data hasn't been changed. Sure, that's the only bit of information you get, but in a lot of cases that's the only one you need.
It doesn't guarantee your data can't be changed, no. What guarantees that is your contact with Amazon.