If they own the copyright, they are free to relicense a piece of data
Sorry to be pedantic, but replace "a piece of data" with "a work of authorship". If there isn't the creative work of a human being involved, it's not copyrightable. And then we get to this:
17 CFR 102(b) In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.
And that means that even when the hand of man is involved, a lot of things are still not copyrightable.