I think Facebook does not strictly ban it, just ban the crypto investment related ones, like ICO.
In the past 2 months the ban had been reviewed and relaxed, It is just the ICO campaign that could have a struggle because of the level of scam perpetrated by the project teams. I understand that the social media is trying to protect themselves and investors. In a space with over 80% scam allegation, it is difficult for such media not to be concerned, and a lot of money is moved now on this space.
