This appears to be a textbook example of a SLAPP (Strategic Lawsuit Against public Participation)! Unless deep pockets are on your side, an opponent can use the legal system to their advantage until you run out of money, patience, sanity or all three!
Seems odd that anyone requesting public records legally under FOIA can be sued.
Unless there’s an Anti-SLAPP statute that allows you to put a quick end to the SLAPP suit. About fifteen seconds of googling tells me Rhode Island has one. If it’s anything like the California one you can shut down a SLAPP lawsuit from the git-go, and get attorneys’ fees for your troubles.