Roman Catholics don't teach that. And I'd consider Roman Catholicism to be a pretty significant religion.
So, once again; you = fail
Uh, sorry, incorrect.
The Roman Catholic attempt at ecumenism is nothing more than a blatant "if you can't beat them join them". In other words, as they slowly lose control over the world's Christians they are simply trying anything possible to stay relevant.
See if this helps you understand;
This means, for example, that Catholic-Orthodox dialogue or Catholic-Anglican dialogue constitutes ecumenism, because both Anglicans and the Orthodox are validly baptized non-Catholic Christians. But ecumenism doesn’t cover Catholic-Islamic dialogue or Catholic-Hindu dialogue, because Muslims and Hindus don’t baptize in the name of the Holy Trinity. The Church describes this kind of spiritual activity with non-Christian religions as “interfaith dialogue.”
While we’re defining terms, we should note that when dealing with common worship among Catholics and other Christians, we must distinguish between communicatio in sacris (sharing in the sacraments), and the more general communicatio in spiritualibus (sharing in common prayer).
Generally, the Church encourages communicatio in spiritualibus between Catholics and Protestants, but strictly limits communicatio in sacris to a handful of sacraments, and even then only between Catholics and members of an Eastern non-Catholic Church (see Canon 844). By “Eastern non-Catholic Church” we mean an historical Eastern Church (Eastern Orthodox, Oriental Orthodox or Assyrian Church of the East) whose sacraments and apostolic succession the Church recognizes as valid. This is different from Protestants (including Anglicans), whose claim to have valid sacraments and apostolic succession the Catholic Church does not recognize.
http://www.catholicculture.org/culture/library/view.cfm?recnum=6056