They are indeed.
But the computers which control launch and targeting operations predate mice by decades. Launching is usually an affair involving lots of panels coated in blinkenlights and big clicky buttons, switches under panels, and then, finally, two keys, and a button push.
Fun fact: the soviets designed their launch control rooms in such a fashion that one person could turn both keys.
Here's someone's snapshot of the control room I'm thinking of - which was a standardised design. Got to push the button!
https://www.flickr.com/photos/tpeddle/11427536443/
Anyway. Take your point, but it'd still require a pretty high level of general ignorance to mistake this for any variety of authentic threat.
