I think the most popular platform of cryptos isn't Facebook..The people who are trading BTC or other coins, they get information from crypto related sites and not from Facebook.
It is true that FB is one of the most popular way of advertising, but it is not the only one.

On the other hand, Facebook would like have own crypto currency, so the message of banning ads isn't too trustworthy.

These two facts can explain, why haven't these news effect on the prices.