How does Philip Roth use imagery in American Pastoral?

Imagery:

“You fight your superficiality, your shallowness, so as to try to come at people without unreal expectations, without an overload of bias or hope or arrogance, as untanklike as you can be, sans cannon and machine guns and steel plating half a foot thick; you come at them unmenacingly on your own ten toes instead of tearing up the turf with your caterpillar treads, take them on with an open mind, as equals, man to man, as we used to say, and yet you never fail to get them wrong. You might as well have the brain of a tank."