Frustrated tenants demonstrated against the lending practices of New York Community Bank yesterday in front of City Hall. They were joined by the City Council speaker, Christine Quinn, who urged state banking officials to delay a proposed merger between NYCB and Atlantic Bank over charges that NYCB has approved loans to many of the city’s worst landlords. A report released last month by the umbrella group Housing Here and Now (Make the Road by Walking is a member of the group) found that more than 200 buildings financed by NYCB had extensive housing violations, leading advocates to accuse the bank of ignoring repair clauses in its mortgage contracts.