Not only that, but Dewey almost certainly would’ve lost the state without Wallace, who got 8%, on the ballot. Dewey was the popular incumbent governor, and Truman wasn’t a great fit, given that he was from a Midwestern/southern border state (as was his running mate). Yes, Dewey lost the state to FDR, but if he only lost it by 5 to another native son, he should’ve been able to do better than a 1% win dependent on a third party’s performance against someone with no ties to the state.
The North East has always been very Atlanticist. NY respected Truman's tough line on the USSR, as well as not going back to the dangerous era of isolationism, like after WW1. As well as Truman building up alliances with Canada and Europe.