Comment by antonvs

> I would say that by the letter of the law, and by longstanding convention,

Those are two different things, and you're confusing or conflating them.

"By the letter of the law", certainly if we're just talking about RFC 854, there's no mention of shells, or some of the other constraints you're projecting onto it.

"Remote user access to service hosts (i.e., remote terminal access)" is perfectly consistent with someone accessing a MUD.

When it comes to convention, though, which is influenced by pragmatic issues such as security constraints, you have more of a case.