My generation during Lent used to fill little cans with dimes to 'ransom pagan babies' and we were taught that every person not Catholic, unless led by their own long-ancestral roots in a Protestant religion, had a ticket to Hell.  No one mentioned, at least to me, the ultimate destination of inhabitants of  countries with multiple gods to appease.  

I'm sure there is a seed of "truth" in every expression sincerely seeking God, but since God alone is Truth, we'll NEVER know it all as we're simply not God.  Maybe since the Reformation...or maybe since long, long before organized, routinized, mandated Christianity, people clung to their own culture in living their lives.  It seems to me what we're dealing with is simply culture -- not dogma, not the Magisterium, not even Tradition -- but simply ways people feel more comfortable relating to the numinous as it speaks to them.  Why are unity and uniformity so freaking important it has caused pogroms, wars, inhumane acts and all this angst?