Alex757,
If your profile is correct, I'm glad you're showing an interest. It's a career without a dull moment for sure.
With a loose row of seats, even if the pax can find other empty seats, the risk of a unsecured flying object is too great with turbulence or even if another problem developed later which could require an emergency landing at a very short field and even exiting the runway where things really get rough. I've spoken with a few who have experience those, and they can be violent. A row of seats flying would be a threat. Having the long, wide runways of JFK appearing under your nose once the problem is figured out is too easy to pass up. Add to that the knowledge that it the major airline base of the company in question and the likelyhood of a spare aircraft or another flight to accommodate your paxs seals the deal to land there.
I would also add the flight was found to have 20+ rows with bad seats. It could have been a life threatening event in the event of a simple aborted takeoff. The RTO autobrakes setting on the B757 is very efficient for stopping and very abrubt. I'd bet most of the 20 rows would have broken off if that occurred and the possibility of serious injury or death in the event of infants and small children being held in the laps of the typical flight is something I really don't want to consider.