IANAEG (...Not An Evil Genius), but it seems safe to assume that a lot of folks in that line of work do not share much of your worldview or value system, to need to do any "rationalizing" before doing such things.
(Actually, you might want to read a few works of fiction which feature well-written Evil Geniuses. Or some "I was a CIA agent..." biographies.)
(Actually, you might want to read a few works of fiction which feature well-written Evil Geniuses. Or some "I was a CIA agent..." biographies.)