how do you claim ownership of data you release publicly at no charge to the users? how do you enforce anyone who copies it by hand or programmatically, does the minimum work to derive some insight and then copyrighting that? You can't. Once it's on the internet, anything you release will simply be relinquishing control.
It's foolish to assume that the lawyers and the justice system will help you out. This is simply not a case of somebody pirating a movie and slapping on their own copyright.
CFAA was how craigslist won but that's been thrown out thanks to the EFF lawyers.
Going forward, there will be little to no recourse for "web scraping public data".