How does Steinbeck ironically characterize the modern age with the use of the mouse hunt?

In "The Leader of the People," modern life, that is, the generation of Americans who grew up after the West had been settled, is juxtaposed with the previous generation. Representing modern people are Carl, Jody's father, and Jody, a young boy. Representing the previous generation is Grandfather, who was the head of a wagon train that crossed all the way to California. Jody's big excitement in life at the time Grandfather comes for a visit is a mouse hunt. The hired hand has just fed the cattle the remains of a haystack, and the soggy leftover hay is teeming with mice. Jody is hoping he and the dogs will be able to hunt the mice, but he has to get permission from his father first. 

More than anything, Jody loves to hear his grandfather tell stories of the wagon train and how they fought off Indian attacks. Carl, on the other hand, wishes the old man would talk of something else because he has heard the stories repeated too often. 

When Jody tells Grandfather about his planned mouse hunt, Grandfather teases him, saying, 

"Have the people of this generation come down to hunting mice? They aren't very strong, the new people, but I hardly thought mice would be game for them."

Jody explains that it's just a game and admits it isn't much like "hunting Indians." Grandfather then references a time after the westward migration when the new white settlers "were hunting Indians and shooting children and burning teepees," and says that that "wasn't much different from your mouse hunt." 

Steinbeck uses the mouse hunt to satirize the modern generation in two ways. First, the modern people don't do grand things anymore. Grandfather says, "the westering was as big as God," but now "westering has died out of the people." Now they concern themselves with petty things that aren't challenging, represented by the mouse hunt. Second, Steinbeck satirizes the white settlers who, upon arriving in the West, brutally killed innocent Native Americans. Steinbeck implies there was no heroism or bravery in that conduct. The fighting Grandfather had done against Indians had been in self-defense, but those who cruelly attacked Indian settlements were killing people who were as defenseless as Jody's mice. 

Although Carl is unwilling to learn from Grandfather's perspective on Carl's generation, Jody is, leaving a spark of hope that the third generation of white settlers might regain some of the greatness of their grandfathers.