I'm very surprised they gave out this information. I'm not talking about the mistake, I mean the actual request. In the UK I don't think you could even get a production order for this. Like, it's effectively getting Communications Data simultaneously against thousands of people not suspected of any crimes?? Like, do people know that by emailing their local government their email address is now free for scammers to re…
Yes, you are as far as I can see correct. The request should have been rejected as overbroad and against data privacy laws (in so far as they exist), or the purpose of the request could have been verified and then they might have seen whether or not there was another way to let the requester do their work without giving them the data they requested (see another comment of mine for one suggestion).
Moreover, the requester is not required to give a reason for the request.
https://www.muckrock.com/place/united-states-of-america/wash...
https://www.rcfp.org/washington-open-government-guide/ii-exe...