If the structure of the service offering exceeds the limits of available technology, then the structure of the service is at fault and needs to change -- wishing away the bad people doesn't work, nor does pretending the issue does not exist (their current strategy) until advertisers are forced to threaten them

The option available to them is clear, it's just not something anyone is willing to accept: connecting untrustworthy anonymous third parties to the bedrooms of 5 year olds cannot be done safely within the limits of existing technology.