Mailbox and Posteo do have transparency reports (https://mailbox.org/de/pressemitteilung-transparenzbericht-2... and https://posteo.de/site/transparenzbericht). Both also support privacy groups via donations (https://mailbox.org/de/post/mailbox-org-spenden-2018 and https://posteo.de/site/wirunterstuetzen). Posteo also hosts privacy related events (https://posteo.de/lab/).

1. Their revenue comes from the users, i.e. they are not the product.

2. Compare the privacy policy of Google and these companies.