> ... "the added cherry from the 'security' community saying that hosting your own email server for confidental emails is no big deal."

Literally nobody (sane) in the security community would ever say that. On the contrary, they'll tell you that running your own email server for any reason is a whole can of worms that nobody wants to mess with, and if you give them twenty minutes of your time to listen intently, they'll list you a whole laundry-list of reasons why.