But does that mean its okay for them to sue anyone who does? If they make the information public, how could they think they have a right to keep their data private from applications they think could be a competitive threat? Should Walmart sue Target if target scrapes walmart prices to help make decisions about their own online pricing schemes?

In what way is it "their data" if they release it to the public? The law is pretty clear about this--facts can't be copyrighted. They don't own the facts. They don't own the bits that padmapper is referencing. All they own is the db records for the posts that originated the information.

Imagine if they had a CL user meetup in public somewhere, and then they charged users to use a megaphone to announce that they were selling something. Someone writes down the information and has their own meetup for people who couldn't make it to the free, public CL meetup. Whats the difference between that and what padmapper is doing, except that padmapper is getting the information second hand?

If CL thinks they have a right to their data, they should be suing google should they?