They charge that the Contras were awful human-rights abusers. While there were individual abuses by the Contras, they never made it policy to use human-rights abuses as a systematic element of their strategy. The Marxist Sandinista government did. This is why two of the Contras' most prominent leaders, Alfonso Rebelo and Arturo Cruz, were Social Democrats and disaffected Sandinistas. In the end, it was military pressure that made the Marxist guerrillas in El Salvador opposing the elected government there and the Marxist government in Nicaragua both come to the negotiating table and eventually make peace.
It's an old saying that if you find a turtle on top of a fence post, it didn't get there by accident. Nor was it an accident that Central America, and Latin America generally, underwent a democratic revolution in the 1980s and afterward. Honduras has had six free elections since 1981. Guatemala made a transition, with Reagan's support, to democracy in 1985. In El Salvador's crucial 1984 elections, the Reagan administration backed the Christian Democratic (center-left) candidate for president, precisely because he was better on human rights than the right-wing candidate, who was associated with the death squads.
At the beginning of Reagan's term, Argentina, Brazil, Chile and Uruguay were military dictatorships. Nicaragua had just fallen to a communist insurrection, and El Salvador seemed set to be next. By the end of or shortly after Reagan's term, Argentina, Brazil, Chile and Uruguay had democratized. Nicaragua held elections won by the opposition, and El Salvador became a model in the region. That John Negroponte was crucial to the policy that affected this revolution should be a recommendation, not a criticism.