Yep. The decision for Google to have access to the contents of my email is mine, not Amazon's (or whoever else). It's the decision I make when I use a Gmail account, and it's up to me to decide that based on Google' privacy policies and reputation.

If I don't want Google to have any access then I'll use a different provider or self host my email. If I want to publish all of my emails publicly that's also my decision.