Not all software is made public and used in workstations, especially not in military
(Made-up but plausible example)
If the physical disconnect between killing a person (e.g. UAVs) wasn't enough to make that task easier then further offloading the decision of who to target might help.
The physical disconnect hypothesis isn't really borne out by the lack of concern for collateral damage in pre-firearm warfare, when killing was mostly done face to face, compared to today.
Guess which one of those is more trigger happy.
People don't feel nearly as stupid as they ought to for being complicit in the 30-40yr that lead us to where are now
That would be back end only, not all software has a gui.