Kennedy is a high risk airport, with many problems. The airspace is highly restricted by other airfields and noise. There is a high number of aircraft movements into the New York airspace going to a variety of different airfields including ones on Long Island etc. Air Traffic Control is very busy indeed and although relatively safe suffers from an inflexible attitude often leading to approaches with high crosswinds when an into wind runway is available. The landing aids are often not available and so you are often forced to fly less reliable, more demanding approaches in marginal weather conditions. The taxiways are often very congested and the chances of a ground collision are probably the highest of anywhere I have flown into.

None of that in itself is beyond any pilot to deal with but it all means you are working significantly harder than at other airports and this reduces your ability to deal with the unexpected, thus the risks of operating into JFK are higher than at other destinations. The risk is well within safe limits and thousands of flights arrive and depart safely from Kennedy every week. But if you were to assess the risk of flying into Kennedy against say Heathrow, the chances of an incident happening at Kennedy are higher.

As to the other incident, without being fully cogniscent of the situation and never having flown into St Kitts or operatted the 777, I cannot make any sensible contribution without it being uniformed and pointless speculation.