It doesn't matter. It's a copyright issue. Craigslist has the right to protect their copyright, it can be proven that they have a unique database, and it can also very likely be proven that the scrapers knew they were doing something illegal (e.g. willful infringement) when the scraping took place.
As far as I know, there is no database copyright in the US.
And you'd be proven wrong by a simple google search on "database copyright"... first hit [1] shows a compilation of laws and court rulings that support copyrighting collection of records... and this stuff has been around for a decade or more.
As far as I know, there is no database copyright in the US.