AFAIK, most if not all states subtract Traditional IRA contributions from the income they consider taxable. How that gets done varies by state. On my own state return (Colorado), I simply copy over the "taxable income" number from my federal return, and since that is after subtracting IRA contributions then I get the same benefit on my state tax bill.

Best as I can tell, the NY tax return pulls over your federal "adjustments to income" (which is where IRA contributions get reported on your federal return) on its line 18 and makes that same subtraction to get your state-level adjusted gross income. I couldn't find anywhere a IRA contribution would get added back to make it taxable.

In a similar way, if you did not qualify to claim that deduction on your federal return, then you wouldn't get it deducted on your state return.