Yes we should. The misunderstanding arises from the lazy media term 'hypersonic missile.' The challenge of this new threat is not that it’s hypersonic (faster than Mach 5). The problem is that it's not ballistic.
Its full name is the 'Non-ballistic Hypersonic Maneuvering Missile'. These designs should be fast and maneuverable in terminal, ideally between 30km and 10km. That's no big secret, it's just hard to do. A fully endoatmospheric vehicle with cross range + pitch turns under 30km at hypersonic without overheating, breaking apart or losing the aim point is basically the holy grail.