

No.
Use S/MIME or PGP and directly encrypt emails to your recipient. This is the only E2E encryption available to email.
The best metaphor for email I’ve found is that you’re writing your message on a postcard and handing it to your neighbor closest to the destination, who hands it to her neighbor, and so on, until it gets there. There are usually fewer hops, but also your email is broken into packets which could go through god knows how many routers, each of which can read your email.
E2E requires setting up a private key; RFC 821 provided no such mechanism. Your only option is out-of-band negotiation, like PGP.
There is a good proposal out there that sets mail headed announcing that you accept encrypted emails, and includes information about your ID, which clients could parse and verify against public key servers; it hadn’t really gained a lot of traction, as it causes issues for data harvesters but also at the end user side. Like, how is notmuch and mairix supposed to handle these? They’d need permanent access to your private key to decrypt and index the emails, and then now your index is unencrypted.
There’s been a fair amount of debate about this, and it’s a lot of work that would need coordinating between teams of volunteers… it hasn’t made much progress because of the complexity, but it’s a nice solution.
Hold on a tick.
Specifically blacklisting a group of users because of the technology they use is, by definition, “targeting”, right? I mean, if not, what qualifies as “targeting” for you?
And, yeah. Posting a sign saying “No Nazi symbolism is allowed in this establishment” is - I would claim - targeting Nazis. Same as posting a sign, “no blacks allowed” - you’re saying that’s not targeting?
I know we’re arguing definitions and have strayed from the original topic, but I think this is an important point to clarify, since you took specific objection to my use of it in that context; and because I’m being pedantic about it.