Not all computers are Intel or AMD and not all Intel or AMD computers have the "features" to which you refer. Even more, nothing requires these computers to be

Not all computers are Intel or AMD and not all Intel or AMD computers have the "features" to which you refer. Even more, nothing requires these computers to be connected to the untrusted network. ME requires an internet connection. The message encrypted on the user-controlled computer can be moved to the "mobile phone" via a wired local network, serial link or removable media. Is such transfer to and from the device made difficult by the way these mobile phones are constructed and configured? Yes, and probably this is intentional. Companies want user data and the way they get it is by encouraging users to store data in the "cloud". Most importantly, these Intel and AMD based computers are not the only computers capable of encrypting messages. If ME scares you then do not use computers that have it. If you have computers with ME then disconnect them from the internet and get a computer without ME for your internet needs. This message was typed on a computer that does not have ME, would not be considered "desktop" and would probably not qualify as "modern". It makes no difference. No problems encypting messages on it.