You’re only thinking of Manhattan. In Brooklyn and Queens there are entire neighborhoods that observe the Sabbath, where the streets are closed for children to play while their fathers attend synagogue and their mothers rest on the day of rest. Bronx on Pelham Parkway, too, and I think Riverdale (no relation to Archie), and some parts of Staten Island.
Still a small overall share of the population. Think of the voting patterns as a proxy.