As for Vito: The man who killed Fanucci for trying to extort a couple hundred dollars from him wouldn't be likely to sit still for that "oily hair/silk suit" insult--and an attempt to extort $250k and 5% of the gross of "all four hotels--Mister Cor-lee-own-eee."
But that was alot of money to Vito at that time. Also, Fanucci got Vito fired from his job, throwing the family in to poverty and near starvation. This lead Vito to his life of crime. Not to justify murder, but Fanucci brought very real and serious harm to Vito and his family.
