NYC Friends To Confederacy?

Civil War's dirty secret about slavery - CNN:

"...To see this, start by considering the response of New York City to secession. On January 7, 1861, after the secession of South Carolina but before any other state joined in rebellion, Mayor Fernando Wood delivered his annual message to the New York City Council. Would the mayor of the largest and wealthiest northern city denounce the southern cause? Rally his fellow citizens around the Union and its president-elect, Abraham Lincoln? Perhaps lament the necessity of a bloody moral struggle to abolish slavery?

Wood did none of these things. Instead, he announced that New York offered 'friendly relations and a common sympathy' with the 'aggrieved brethren of the slave states.' He then offered the bold proposal that New York City secede, as well, forming an independent city-state. This move, he argued, 'would have the whole and united support of the southern states' and would allow the city to avoid breaking off its existing relationships with the slave states.

Of course, New York did not secede from the Union. But why did this northern mayor, along with many of his fellow citizens, so dramatically embrace the southern cause?"