Lilo, the novel states that, indeed, it was his father's murder (that followed upon the heels of his being so verbose with the local mafia chief) that prompted Vito's avoidance of quarrels, threats, etc. It also states that Vito taught Tom to never threaten, to reason only.
"Generosity. That was my first mistake." "Experience must be our only guide; reason may mislead us." "Instagram is Twitter for people who can't read."
