If I don’t “sense” that killing is wrong, and/or I can’t explain why it is wrong, it is still wrong.
Counterargument: Amalek, and Zhids.
PAA: There is your sense of right and wrong (morality), and then there is absolute right and wrong (the RBSO). They will not be the same; at times even the Malachim didn’t believe Hashem was in the right (e.g. the Asarah Harugei Malchus).