Ads in Gmail are not related to your emails: https://support.google.com/mail/answer/6603
At the moment they aren't, but they used to be and very well could be again in the future. Also, that link says nothing about Google not "reading it, learning from it, modifying it and hiding some of it from you", when it comes to your emails, which is GPs stated concern.
Google still saves and parses every email it gets and likely uses that data for a number of purposes. No longer directly targeting Gmail ads with it really doesn't do much for people who are concerned about Google and privacy issues.
Re:Google launches AMP for email
by joshuamorton on Wednesday March 27, 2019 @12:36AM
(#19498204)
>Google still saves and parses every email it gets and likely uses that data for a number of purposes.
Sure, but so does literally every email provider. Storing your email and spam classification are pretty much the two biggest features an email provider can provide.
This is like objections to "algorithms" or "chemicals".
This needs to be explained to people, as most still think that Gmail just displays all of your private E-mail with a nice interface, FOR FREE!
The "FOR FREE" part is really the killer, I found that people are amazingly resistant to the idea of paying anything for E-mail, even if compared to their other utilities (power, water, internet, TV?) it is extremely cheap.