Never i think. They will makes another coin for them, ex: FTC
Facebook has recently banned the advertisement of the all types of the crypto currencies which shows that facebook has two things in the mind, either it is totally going against all the types of crypto or it has already made some deal with any of the crypto currency and soon it will be disclosed for everyone. Just wait and watch because the way facebook has highlighted crypto issue, there is going to be some news at the back end.
They banned it yes but then again they don't ban cryptocurrencies. Those ads were all paid if you saw there are promoted ico until now. Furthermore, that banned is more specific for the ico or promotions that is only intended to scam Mark Zuckerberg did it to avoid those scams. As i read some information on it i forget where so i can't give the link.
Who are they to ban anything? They can try to stop people from using it there, but that is all they can do. I understand shy they banned advertising of icos and bitcoin doubler's, then online mining, and million other thngs, some people created so much spam, my page there is filled with so many stupid posts, long posts that promise a big profit just if you go there. They should do that long time ago, and clean their yard a bit. Twitter will do something similar, over there situation is not better.