The problem here is the Syllabus of Errors itself. Fr. Joseph Ratzinger was one of the theologians who suggested that he be laid aside and that the errors be addressed from the context of the Church today.
When he became the Prefect for the Sacred Congregation for the Faith, he continued with the same idea and now as pope. Many people have misunderstood him and he has tweaked his positions too. Error remains error. There is not debate with that point.
What changes are the context and the players. At the time when the Syllabus was written, the Church was rooted in predominantly Catholic nations. Even though she had little temporal power, she had a great deal of political influence. Many political leaders were leaning toward Socialism and Capitalism, both them are very dangerous to the faith. Socialism tries to annul God by promoting atheism. Capitalism tries to annul God by replacing him with wealth and power.
The Church agrees that no one should be forced to embrace the faith or any faith. Therefore, she condemns any attempt to do so. People must freely embrace the faith. However, she does not say that people can embrace error. No, it’s not true that people are free to become Protestants, Jews, Muslims, Hindu or other. The Church has never said this.
Even Mother Teresa is often misquoted on the matter. She said, “A Muslim must be a good Muslim, a Hindu a good Hindu and a Christian a good Christian.” She did not say, “You can choose to be a Muslim, Hindu or Christian.” She was speaking about those who are born into these faith traditions. She was coming at this from the teachings of Bl. John Paul, which she knew very well. There are shadows of truth outside of the physical boundaries of the Church. If you follow those truths, whether you discover them in Islam, Hinduism, Judaism or Protestantism, they will lead you to Catholicism. The individual has a moral duty to get to know the meaning of these truths and to follow where they lead, because we’re bound to follow truth.
Today, the Church cannot use the same language as that of the Syllabus of Errors, because she’s not speaking to the same world. She has to address these errors in our context, using our language and the resources available to her today. Cardinal Ratzinger once told his students that the Syllabus of Errors was never intended to bind future popes. They were free to address error in whatever manner seemed prudent to them. The key is error. The Church continues to address error. That has not changed. She cannot cease to do that. What she says and how she says it is going to change over time. The moral truths that oppose error do not change, just the language.
Fraternally,
Br. JR, OSF