I used to handle the French equivalent of FOIA requests once upon a time when I held a government job and while it is less intricate/complex than getting regulatory approval for anything, it can definitely be much more time consuming. 330,000 pages of material to get through is a Herculean task. It’s not like the FDA have unlimited personnel to do this. Usually handling FOIA is not a full time job of a person, but something to be done on top of their regular full time job in their spare work hours.
Any medical data about any person, even if you redact their name (which you have to by law), you also need their written permission to release it in anonymised form to the public (also by law). Tracking down and gettIng this permission would number into millions of letters I would think as trial data that goes to 330k pages would have the medical data of maybe a dozen people per page?
You also have to redact anything that might be proprietary to the company, Pfizer, in this case and the response has to go through their review process before released as well.
Usually once you have the FOIA response done per above, it then also has to go through review by government public affairs officers and government solicitors to ensure it has been done correctly.
There are also very limited budgets for FOIA requests, government agencies are only allowed to spend a small amount of resources on answering them. The FOIA handler has to record the cost of every hour worked, every phone call, every email, all postage, and a per page printing or copying cost. So you have to do accounting on top of answering the request and that takes time and god forbid you go over the money limit the agency has been authorised for FOIA requests because that is a sackable offence to spend more money than the agency has been given in public trust.
I don’t think anyone is hiding anything. The FDA’s response is reasonable to me because I’ve done FOIA requests before as a government employee.