[nobody9999]

>Lack of TLS support on the sender side and the context goes clear text through relays. Encryption remains the best way to guarantee against eavesdropping.

TLS support only provides a mechanism for encryption across the wires. If your email is stored unencrypted anywhere except your own physical hardware (and sometimes not even then), whoever owns that hardware can (and the likes of Google actually does) read/modify/delete any or all of your emails at their whim.