Francis said there are limits to freedom of speech, especially when it concerns religion. He was answering a question about the deadly attack last week on the French satirical magazine Charlie Hebdo.
Francis is in Asia on a six-day tour intended to build the Roman Catholic Church's following on a continent that holds 60 percent of the world's population but only 12 percent of Catholics.
Robert Finn, head of Kansas City's diocese, is the only U.S. bishop convicted of shielding a sexually abusive priest. Supporters say Finn received conflicting advice about how to handle the problem.
Oscar Romero was gunned down in 1980 after he denounced a crackdown by El Salvador's junta on its left-wing opponents at the start of a 13-year civil war.
Some of the prelates come from countries that have never before been represented at such a high level in the Catholic Church — including Tonga and Cape Verde.
In his annual Christmas Day blessing, the pontiff condemned killing in Iraq, Syria and Pakistan and the "brutal persecution" of religious and ethnic minorities.
Despite detractors within the church, Pope Francis' emphasis on humility and mercy has won him strong support worldwide. He has addressed thorny issues such as Vatican finances and clerical sex abuse.