NYC was the major port for bringing in slaves. One would think that would've been somewhere further south of the Mason/Dixson Line along the east coast. . .but nope. . .NYC all the way.
NYC was a Loyalists stronghold. Slavery was legal in Britain. So it fits. The State however voted against slavery at the signing of DOI, 1776. Only two states voted for it, SC, and GA.
Remember in June 1776, NYC was made up of loyalists? 60 English ships were in NY harbor; The NYC mayor was bribing American troops to join the British. Just days before independence, NYC didn’t want to be part of America; Sound familiar?