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.
I think Facebook is not against Bitcoin as they taking money against giving ads in their site but problem is where there money related there are some people who misguide another people and many men misguided by wrong person through Facebook. So at present time facebook company did not want to take this responsibility or they think that men should not take wrong information from facebook.