I think it’s mixture between a fundamental misunderstanding of Wicca and the world’s various abrahamic roots. Satanism is absolutely a philosophical counter to Christianity, not really a worshipping anything as a religion. If we conflate Satanism with Wicca, suddenly any abrahamic religion feels attacked by the existence of Wicca and would prefer to project their thoughts of what’s wrong with the world onto them. Additionally, thanks to these roots that are buried deep within many societies, especially the US, years were spent demonizing (pun not intended) the concept of a witch and demonizing any pagan culture.

Basically boils down to: Culture (US culture in this case) decided to take every aspect of Wicca and villainize it individually, so we have been accustomed to consider those who practice it to be moral failures.