The National Hispanic Media Coalition joined forces this week with the National Puerto Rican Forum to file negative comments against two New York TV stations that are up for federal license renewals. The coalition, a Los Angeles-based umbrella group, and the New York-based forum singled out WNET Channel 13, a PBS station, and WPIX Channel 11, a Tribune Broadcasting Co.-owned station, for their low Latino employment numbers, particularly in upper management ranks. Both groups said WNET was the worst offender, claiming that 6.4% of its overall work force and 3% of its top management posts were filled by Latinos. George L. Miles, WNET's executive vice president, defended the station's commitment to affirmative action at all levels and argued that WNET's programming "represents all minorities and is the finest anywhere." Coalition president Armando Duron responded that "public TV stations like WNET are under the impression that . . . because they offer better programming, it exempts them from certain legal requirements. We're here to tell them it doesn't."