Because Facebook has not actually bothered to do anything after they stated they would start coming down on fake ads. What you got was an ad, you can thank Facebook for allowing the advertisers to use their platform for yet another scam.
Hi
Go to settings down to Safari delete history and data.
Cheers
Brian
Hi 7vice13,
It could be that downloading content from outside the Facebook app could be downloading with it malware and other bad things.
The virus alert is bogus. iPhones cannot get viruses, unless they are jailbroken. Disregard it.
why am I getting a virus message on my iPhone when downloading content from facebook
