For all X, if you study the effects of X on a complex system hard enough, it will look like X is the dominant factor that explains most of the variation.

I happen to believe peer groups are really important. But other things are important, too, including the adults.

Remove all the middle-aged and older men from a city, but still provide other necessities, and you'll see some terrible outcomes. (This is true in other species as well, like elephants where older males are hunted for tusks.)