They hid it during the depression too. They managed to hide 7 million Americans that starved to death during that one. They hid it so well that when Steinbeck wrote The Grapes of Wrath, nobody believed it was actualy going on.

Darryl F. Zanuck bought the movie rights. He was a patriotic American and was concerned he might be slandering the country he loved by making America look bad if he made the film. He was especialy concerned if the alegations steinback was making wern't true. Like everybody else, the true horror of the situation had been hidden from him.

Zanuck hired private investigators to read the book then dress up as bums and go to the indigant labor camps in California to see if the conditions really were as bad as Steinbeck made them out to be. After spending a few days in them, the PIs reported back that they were worse than what Steinbeck said they were, and Zanuck, being an honest man, made the movie true to the book despite his own personal reservations.

True story.