Source? I'm only seeing a single digit number of commits from Amazon emails out of ~57k total commits:
elasticsearch $ git shortlog -nes | grep -i 'amazon'
elasticsearch $ git shortlog -nes | grep -i 'amazon'
You're not required to contribute with your amazon e-mail address, and I see a lot of people who don't due to inertia or because they want to avoid tying their identity their employer.