I believe the expression “hot buttons” has its origins in military jargon. Those who would be most likely to know the true origin of this expression are army doctors, psychiatrists and especially, army chaplains.
Psychiatric casualties are inevitable in war. The idea behind identifying and utilizing hot buttons is to reclaim the soldier broken by combat fatigue and get him back on line ——- the battle line; the front line.
“Hot Buttons” then are a set of motives or motivators or a single and often very personal casus belli or justification to carry on and re-enter the fight. A soldier mentally and spiritually broken and prostrated by physical fatigue and the terror and horror of war can be made to rise once again to become a functional member of a combat unit if just the right hot button can be identified and pushed.
One source described this as “situational manipulation.”
Another source called it “the one-two punch of chaplain-psych specialist.”
The chaplain engages the soldier in a mind-probe interview to identify the hot buttons. After some consultation a Psychiatric Specialist, nominally an enlisted man, then presses the button.
“For God and Country”
Pro Deo et Patria
If you have a better or more authoritative source or explanation for this commonly heard expression — “hot buttons” — by all means you are welcome to post it here.