Facebook is not against Bitcoin but rather intends to avoid the situation of misleading its community members through its paid advertisement. Users of facebook can post crypto and Bitcoin related topics on facebook without any penalty.
Yes you right, facebook is trying not only to protect it users but also to protect the image of the platform so that it will not be known for crypto scam. Many people has been scam through facebook medium using cryptocurrency, and they know nothing about blockchain. All facebook users should be careful there's no site that offers free bitcoin and almost all the mining advert of facebook are all scam don't be a victim.