Essentially gerrymandering. They folder super blue areas of Bergan county into the district to overwhelm the red voters.
If Paterson and Passaic are in your district, than Passaic County is the problem; what “super blue” area of Bergen County is lumped with Sussex?
Maryland eliminated a formerly Republican won congressional district as well. It seems that the courts are ok with extreme gerrymandering in Dem states like NJ and MD, but overrule such districts in Republican majority states.