Two weeks before the 60th annual Puerto Rican Day Parade in New York City, Andrés Otero was his own grand marshal of the Loisaida Festival, a neighborhood celebration on the Lower East Side of Manhattan. Decked head to toe in the colors of the Puerto Rican flag on Sunday, he drove down the middle of Avenue C in a red scooter festooned with stickers of conga drums and roosters.

As salsa music played and grills smoked at the popular street fair, Mr. Otero, 75, was as buoyant as the rest of the crowd. But his mood darkened when he was asked about Oscar López Rivera, a Puerto Rican nationalist militant recently released from federal prison after 35 years, who will be honored at the parade on June 11.

Mr. López Rivera, 74, was a member of a terrorist organization fighting for Puerto Rican independence that carried out 120 bombings in the 1970s and 1980s, including two in New York that killed five people. He was never charged with murder, but was convicted of seditious conspiracy for plotting to overthrow the government. President Barack Obama commuted his sentence.