I think "no hello" evangelists should emphasize that you can say hello if you want, as long as you follow up with your actual question/request in the same message. The point isn't that the "hello" itself is a critical waste of some human resource, but rather that interrupting somebody with "hello" and then making them wait for something actionable is disruptive and frustrating.
This may seem obvious to many, but I don't think it's universally understood.