I think what the OP is saying is that there's no right, stated or implied, to wrap Craigslist data in your own UI. If you want to write your own front end for classified ads, you're going to have to bring your own ads to the table as well.
I don't think even Bilton is arguing that CL is not within their legal rights. He is just pointing out that it seems contradictory to their claimed culture of being community-driven, anti-SOPA, wanting to be a public good, and all that jazz.
