LOL, like you send mails to anyone that can be bothered with accepting encrypted e-mails. anyway.
If you really care, just entrust it to you ISP, they are already the man in the middle anyway. You are using plenty of protocols that are vulnerable to man in the middle attacks already so any objections you have to it is just a facade.
You very clearly don't understand how PGP key signing works.(Hint: done properly, it makes MITM for all practical purposes impossible.)