El Reda has been a key component of Hezbollah's, and thus Iran's, evil terrorist agenda for decades, and authorities across the globe haven't forgotten what he's capable of and responsible for. He killed dozens of Jews in Argentina, blew up explosive caches in Thailand, and spied on US and Israeli personnel in Panama. Though it's been some time since he began his terrorist career, the US knows who he is and what he's done, and is now pursuing him legally to bring some justice for those affected by his horrific crimes.
While the US and its allies have long used this bombing as a precedent to demonize and sanction Iran, US diplomats and Argentine police officers involved in the immediate investigation later acknowledged that there was never any evidence linking Tehran. In 2014, a former Argentine spy who had infiltrated the Jewish community claimed that the anti-Semitic police department ordered him to hand over the blueprints to the facility, which suggests this could have been an inside job that was later used by the US and Israel to stoke anti-Iran sentiment for political reasons.