I made the same point last night. There is an air-gap between the comm electronics and the missile fire-control that must be bridged by a human. And I can't fathom a USN sailor accepting an order, even if the codes check out, to launch nukes when the only two countries in range are the US and Canada. It would be obvious that the order is bogus.
That's why nothing about this adds up.
Also, what are the chances that the launch would have been close enough to the weathercam that you can see the length and diameter of the missile? Nil. I'm starting to suspect that the image is fake and "hack" was the planting of the image in the weathercam's system. Maybe there was a plot to detonate a nuke on the ground and then claim that Trump ordered it, or something, and this was manufactured corroboration evidence.