Sure but the public data is still protected by copyright laws. That's why journalists cannot reproduce your blog post verbatim or take your photos and use them in their articles without your explicit permission unless you've released your articles or photos under a Creative Commons license.

Don't get me wrong! I do think that this whole thread is a massive overreaction. A judge might even see this use of data as "fair use". I don't know. I'm not a lawyer. But I do know that "public data" != "can do whatever you want with it".