Yeah, but UIs aren't there for reading; they're for using. If I get an undeliverable because the recipient was bad, then the UI just needs to indicate, "Bad Recipient."
People are doing energy management all the time, and that's not a bad thing. They see something that looks technical at a glance (it's got numbers and slashes and run-on sentences) and that's it. They know they're not technical, and they don't aspire to be technical, so they don't waste energy trying to comprehend the message.
I know plenty of non technical people and they all understand the concept of bounced emails. Error 238B is terrible but "can't deliver email to ben.cornwalll@test.com" and 90% of people can understand they miss spelled the guys email address. It's only after that they their eyes gloss over and their mind shuts down.
It would be reasonable to someone reading HN, since we probably are not scared off by technical jargon. Even if the instructions were spelled out completely, the plain-text formatting and numbers (IP addresses) immediately tell the average user that this is over their head and they ignore it. It's not user-friendly for real-world users.
Seems reasonable to me.