Why Witchcraft has been suppressed
The reason, and the main reason is very plain. The Elite (who actually have been secretly practising witchcraft) are very uncomfortable with the idea of everyday people bettering their own lives. This has always been the story of mankind - Keep the masses ignorant so that the Elite can rule them without any form of trouble.
Witchcraft was actually ILLEGAL in many countries, and during the 1950's in Britian the law was relaxed. I personally think that praying to God is a form of witchcraft in itself.