Even though none of these states voted Republican in the last several presidential elections, there are conservative pockets within those states.
For instance, in NY, Rep. Peter King, a Republican is in the L.I./Westchester area, a Conservative pocket surrounded by a liberal NYC area. King has been known to be mostly in lock-step with Trump/GOP. He did seem to beg that the mortgage cap not be lowered in this taxscam bill but it would seem that he's willing to go along with voting for it anyway, despite that fact that his constituents will likely lose the most of any homeowner in the country as they are predicted to be the hardest hit.
New Jersey also has some conservative pockets and there is a severe disconnect there as the predicted hardest hit area is calculated to be Newark, NJ which is an inner-city and has a large population of black and minority homeowners, many of whom also happen to be low-income homeowners.
Also, just flat out greed and corruption as some of these Congressman look to personally benefit, regardless of how their constituents fare.
Speaking of greed and corruption,
Another day, another lawsuit for Trump Inc.
Jared Kushner and Ivanka Trump Face New Lawsuit Over Financial Disclosures: Report