Is Willy Wonka a slave driver?

He "saved" these Oompa Loompas from their home country where they were being eaten by whatever creature, or so he claims. Has them working at his factory for nothing but chocolate. He blows his whistle and they come running singing their Oompa Loompa slave hymns. I loved the movie as a kid but as I got older I realized the truth. Open your eyes America.