Then shouldn’t they publish the documents showing those giveaways instead which surely makes more sense, doesn’t put AWS customers at potential risk and holds local governments accountable?

The simple thing is to put anything you get your hands on online under the opaque umbrella of public interest. The responsible thing to do is to run with it, find the local governments in those areas and file requests for the records of any transactions to be made public. That would be in public interest. Dumping anything that has a SECRET written on it is not always a good thing.