People will just list in other sections, under code words, just as they do with drug sales. That just makes it more likely that some naive person will end up in contact with a prostitute when they didn’t want to be, and do nothing to stop the use of the site by those who want to buy and sell prostitution services. I really don’t think the Craigslist CEO should feel responsible for this. These were adult women, advertising their availability as prostitutes to total strangers on the internet, and then telling those strangers where to come and meet them. Anybody with a high enough IQ to figure out how to post an ad on Craigslist is smart enough to know this is extremely dangerous.
Setting aside the matter of the whore killer for a moment:
Craigslist is providing a highly visible forum for criminals to advertise illegal activity out in the open. It is reasonable to expect that this leads to an increase in criminal activity involving individuals who might not normally know where to look.