The signatories of this (letter, petition, whatever) are the same folks who profit from creating this Pandora's Box. If you don't want it opened, stop making it?
I’m torn. On the one hand it’s nice that the rank and file take a stand against extreme overreach. On the other hand these rank and file scientists, engineers, whatever are fostering a technology which has so many at-best questionable effects on all of society.
Idealists who “genuinely”[1] want to change the world “for the better”[1] will just move on to the next Interesting Problem if it ends up making the world worse.
There are other valid use cases than war for AI.