Because they believe that Facebook prohibits bitcoin and ICos and other cryptocurrency
The new Facebook policy will not allow announcements of known digital currency exchanges or initial offers of currencies.
Is it to avoid fraud or false advertising? That's why?
Facebook are simply maintaining a strategic distance from undesirable controversies, in light of the fact that if something happened identifying with cryptographic money and facebook is attached to that, they would be under flame again particularly that facebook is purportedly "taking" information from individuals. They are simply dodging issues that can ascend with the reality the a few people mishandle digital currencies.