Originally Posted by
Lefly
Yes, it was that, thank you.
Of course
It was the "going landside if you have a bag to check" part that puzzled me, as I thought there was a bag drop desk airside, so no need to waste time to clear security again.
No, the bag drop for connections is post customs and landside, and you definitely need to go through security again regardless of whether you have a bag to drop or not - there is no airside sans-security connection route at JFK (or at any US airport I can think of) for an INT-DOM connection.