Earlier quoted context omitted.
Yup, the "Spam" button is a true signal. A company I worked for had problems with the number of times people hit 'spam' on the emails (not even a newsletter, but transactional emails), and AWS SimpleEmailService put us on probation. I got to write a worker task that would consume the queue of "someone marked you as spam" from SES and remove them from our email list.
Forgive the naivety, can you explain a little? From what I understand from this: You sent emails from AWS to subscribers. Some recipients hit the spam button in Gmail. You received a message for every email that had been flagged as spam, including the recipient details. Is that correct? What exactly happens when I hit the spam button in Gmail?
This value will usually be an HTTP URL (it can also be a "mailto:"). That (unique) URL (which is tied to your e-mail address) is then followed in order to unsubscribe you from the list.