This is untrue for a simple reason. The thematic core of the series is "War Never Changes" to the point it's even in the descended spinoffs like 76. In short, this phrase means that humanity has a core problem of violence. No matter the context or justification, we will find reasons to kill eachother. Fallout takes a very Hobbesean view of mankind. We are by our inherent nature brutish and violent.
This is shown in two ways in Fallout. The first is that humanity's destructive tendencies in tandem with the advancement of technology was an unstable combination which resulted in the ultimate act of violence: the end of the world. Something that was inevitable. Humans won't stop advancing and we won't stop killing eachother. The apocalypse was the mathematical result of our existence.
The second is that in the absence of law, society, civilization and technology our nature is stripped bare. The Wasteland is a bloody, violent place where the mistakes of human conflict reappear over the most basic resources, in the most raw fashion. Even though we ended the world, it's not enough to satiate our need for violence.
Quite literally all of this is stripped away if it's not humanity that ends the world.