>>Which rocket scientists?
People like Theodore Postol (professor of Science, Technology, and International Security at MIT) and David Wright can be a bit dry, so you could start with Markus Schiller, David Montague and Steven Hildreth quoted in the ACA article you didn't read. Hildreth is a specialist in missile defense with the Congressional Research Service, Schiller is a highly regarded missile expert internationally and Montague was President of Lockheed Martin's missile division- and they don't agree with you or Kim Jong-un. ;-)
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1