The proposal is indisputably harebrained, but the question is why the authors decided to publish it? One of the authors is a former US Air Force colonel.
And in particular why they choose to propagate falsehoods like "Hypersonic cruise missiles are powered all the way to their targets using an advanced propulsion system called a SCRAMJET. These are very, very, fast. You may have six minutes from the time it’s launched until the time it strikes." Lest it be any confusion, scramjets are fast, but are nowhere as fast as ICBM's (Mach 5-10 vs Mach 20-23).
> Lest it be any confusion, scramjets are fast, but are nowhere as fast as ICBM's
I agree that's weird phrasing and incorrect on its face. That said - as I understand it, cruise missiles don't have the launch signature ICBMs have. While it would take longer for a cruise missile to travel the same distance as an ICBM, it might in fact give the target country less time to react if they aren't detected until they are well on their way.
And in particular why they choose to propagate falsehoods like "Hypersonic cruise missiles are powered all the way to their targets using an advanced propulsion system called a SCRAMJET. These are very, very, fast. You may have six minutes from the time it’s launched until the time it strikes." Lest it be any confusion, scramjets are fast, but are nowhere as fast as ICBM's (Mach 5-10 vs Mach 20-23).