Here are some notes from the writing of Card Ratzinger and Benedict XVI:
If a religion teaches a way of life that is not righteous, it cannot be a true religion. Only when man has lost sight of the ability to know what is good and what is true, then all offers of salvation become the same. If we do not have any standards of right living, then all religions are the same.
If the standards for right living are relativized, man remains trapped inside religions. Again, this demonstrates that religious relativism is founded on philosophical relativism. Cardinal Ratzinger points out that St. Paul (Romans 2:14ff) does not say that non-Christians will be saved by following their religion, but by following natural religion.
We have to always bear in mind that also the reverse influence is true as well: Religious pluralism in turn produces philosophical relativism. In fact, Benedict XVI reminded us that "The convergence of differences must not convey an impression of surrendering to that relativism which denies the meaning of truth itself and the possibility of attaining it."
If it is possible to criticize religions starting from the reasons of man, then it must also be possible to criticize them starting from the reasons of man in society, that is from a public religion. Then it becomes clear that not all religions are equally respectful of the good of man in society. It is also clear that the political power that seeks to organize society according to reason not only cannot relate to all religions in the same way, but should also cherish its obligations to the true religion. Of course, if the political power is based on the relativistic democracy, it will not feel any obligation in this regard.
Relativism, in fact, can only express a procedural public reason. When the truth is replaced by the decision of the majority, culture is set against truth. The relativistic presumption leads to the tearing up of people's spiritual roots and the destruction of the network of social relationships