If it was a defensive launch, what were we shooting at? The missile was too large to be attempting to take down an aircraft.
If the target had been a ship or submarine, it’s more likely a torpedo would have been used, so we can rule out defense of an air or sea attack or “provocation”.
The only reasons we’d fire an ICMB/SLBM (other than a training or testing exercise) would be to destroy a land-based enemy target, and that would likely be in response to a foreign government having launched first — or threatened to launch first where we felt launch was imminent.
The latter could explain why the missile may have been scuttled — and why we’re not currently at war with, well, whoever the “bad guy” is in this scenario. They threatened to launch, we fired a missile, they backed down, so we scuttled the missile.
Were this the case, there would likely be a delay in reporting “what really happened” because the President himself would need to be involved in, and would likely make the announcement to nation himself. He’s overseas right now, so a delay of even 12-20 hours would be “reasonable”. Since it’s been almost a full day since the event, and we haven’t gotten word from the White House or Pentagon, we can likely rule out this scenario.