I've read an article and this happens because bitcoin and other altcoin do a lot of promotion in social media. that's why bitcoin should not be promoted in cyberspace.
I don't think the whole issue of facebook and bitcoin is all about bitcoin itself but just that icos where being fraudulent and taking opportunity of investors. So, bitcoin being at the top was being seen as the number one and was being referred to. Otherwise, bitcoin had know issue with facebook.
Yes all about scam ico which want to collect as much as money from investor.
Bitcoin does not have the relation with this forbidden because in the future i guess facebook will have its own cryptocurrency which is legit.