How does Steinbeck view humanity, based on The Grapes of Wrath?
The Grapes of Wrath has many different messages about humanity laced through it, so to argue that Steinbeck had any one view might be too limited. However, looking at some of the themes of the book gives us a good idea about his personal views.
The characters in the book struggle from beginning to end. The almost impossibly harsh challenges they face has been seen as Steinbeck's interpretation of the human condition. He also chose to show these characters helping one another in these times of need and...
that "all people essentially belong together and are a part of one another and of a greater whole that transcends momentary reality, is what removes The Grapes of Wrath from the genre of timely proletarian fiction and makes it an allegory for all people in all circumstances" (eNotes)
We can see that Steinbeck likely felt that humans cause each other unimaginable suffering and pain, but that humanity is also capable of great kindnesses and compassion toward one another. So, he presents two versions of humanity—the predator and the prey. However, that he focuses so strongly on the "prey," if you will, via the Joad family, shows us that he viewed humanity as strong, compassionate, resilient, and even generous.