This is where Dahl bowed to early 70s wokery and erased the oompa-loompas' true identity as African slaves who would dribble for cocoa beans.
Film adaptations have struggled with the fact that oompa-loompas are, however you dress them up, slaves.
From this article which is much more interesting:
https://theconversation.com/from-pygmies-to-puppets-what-to-...