Traditional Catholicism is often criticized for putting inordinate importance on being Catholic. But of course, for the Church, being Catholic has always been a means to an end. The end (or at least one of the primary ends) is the salvation of one's soul. Or as the Church used to put it for the first 98% of its existence before people like Barron came along, the salvation of as many souls as possible.
People (rightly) rebel against the noble pagans of the world ending up in severe torment, so they try to squeeze them all into heaven, and run over centuries of Christian doctrine in the process.
Why not just go back to the old idea of Limbo? A place where the just of whatever religion can exist in natural happiness?
Heaven being a place of supernatural happiness, you cannot go there without supernatural grace. Period, end of story.