Rabbi Avigdor Miller Z”L was once asked “What do you think of certain groups of people who believe that only their beliefs are correct and only the way of life they chose is correct, and everyone who disagrees or acts differently is wrong?”
Rabbi Miller answered ” That is the way it should be!”
This should presumably be taken at the level of “Yiddishkeit or some other way of life,”
but at the level of “my way of Yiddishkeit or yours,” we should presumably apply
“eilu v’eilu divrei Elokim Chayim” (both are the words of the Living G-d).