Well, if you describe them as "deranged", then by definition the serial killers were not choosing their actions lucidly.
Timothy McVeigh, on the other hand, wasn't deranged. He wasn't mentally ill. He chose his evil lucidly.
People who join the KKK and who participate in lynchings aren't psychotic, either.
The vast majority of people who helped exterminate the Jews in Nazi Germany were quite sane.
Thousands of rapists move through the world as otherwise normal workers, friends, partners, husbands, sons, and fathers.
All of them choose evil lucidly.
Edited by nator, : No reason given.