Evil or not (and he was), the man's influence on popular culture is immeasurable. Therefore,
RIP FF 
Whaat? 
This dude is responsible for several cruel, and I mean really cruel, murderers. Cultural influence is not something that determines whether somebody is FF or not. The comparison may be a little off, but Hitler and Stalin also had cultural influence, yet they were the greatest mass murderers in history.
I never said the murders themselves were justified. (Although it's also important to note that Manson himself never killed anyone.)
Hitler and Stalin hardly ever had cultural influence.
So far as I know, Ernst Kaltenbrunner, the man responsible for the operation of the Nazi concentration camps, never personally murdered anyone. But he gave orders, and he is responsible for the many gassed, killed for insubordination to a gangster order, worked to death on starvation rations, subjected to obscene pseudo-medical experiments, tortured, or subjected to spontaneous cruelties of guards ranging from having dogs attack helpless people or having arriving inmates (usually children) cast directly into raging crematoria when the supply of Zyklon-B ran out for the day.
Yes, Kaltenbrunner was unjustly hanged for his role in the mass murders of the Nazis. He should have been burned at the stake.
OK, Kaltenbrunner had some cultural influence by extirpating what had been the rich potential of the Jewish population of Europe. Europe other than Britain is basically a museum of its past glories, in contrast to America and Britain, where people that the Nazis determined unworthy of survival got to survive. In view of the stultifying effect of Stalin over culture in the Soviet Union and in immediate the post-WWII Soviet bloc, I would have to say that Stalin had cultural influence. Destructive influence.
