I always have my problems with personality cult, no matter if it's about favourite or about much-hatet personalities.
It is not only dictators who enable mass murder. It's also people, folks, soldiers, who do not only participate but accomplish evil things at the end, based on personality cult and on following ideologies.
Adolf Hitler could have been brevented. His intentions, to "extinct" the jews, to "eliminate" the Marxism and so on, were known publicly from the beginning. Hitler is only one, out of thousands of potential and real killer.