Microsoft reads your emails too. Any service that has junk mail filters does. Gmail just does it more effectively.

This isn't enough reason for me. You could encrypt your emails if you don't want google to read them.

I ceded long ago that email is not a private communication medium. Even when the communication of the message itself is encrypted (which on Gmail it is), the messages probably sit as plain text on the email server. More people than I can count can read my Gmail messages - but the same is true for my school email, was true for my ancient Juno account, and is true for anyone using an email account through their ISP.

You mind when the robot spiders them? Idk, doesn't bother me.