Substitute for Google's silicon assistant a human personal assistant of the intended Gmail-using recipient. "If any person other than X reads this proprietary poetry, they owe inerte big bux!"

The mail recipient chose Google to handle his email. He could also have chosen some random human to assist him with handling his email. There is no difference.

If you wish to correspond with such a user, you must trust him not to show your email to parties you find obnoxious. If he betrays you in that regard, your beef, such as it is, is with him, not the parties he hired to handle his email.