“Essential Difference” as a basis for inclusion - not exclusion; an example from Catholicism[in progress]

I will initially compare mainline Catholicism with a mainline, popular 'haredi' Orthodox belief regarding meaningful life and salvation (so popular, I don't even bother to give "chapter 'n' verse" to prove it exists). The Catholic Church teaches the doctrine of Extra Ecclesiam nulla Salus; "Outside the Church there is no Salvation". The Catholic Church in the“Dogmatic Constitution on the Church”), asserts their conviction in the necessity of faith and baptism (Mk 16:16, Jn 3:5), and the Catholic Church as the body that is thereby entered into (emphasis of course mine); “Hence they could not be saved who, knowing the Catholic Church was founded as necessary by God through [j.c.], would refuse to enter it, or remain in it…those who have not yet received the gospel are related to the people of God [i.e, the Church, the specific body who are the 'people of God', a status not shared with all humanity] in various ways. There is first the people to which the covenants and promises were made, and from which X was born according to the flesh…:in view of the divine choice, they are a people most dear for the sake of the fathers, for the gifts of God are without repentance (Rom 11:28-29); [left out of the quotation is calling them “enemies of God, which is in v.28]…But the plan of salvation also includes those who acknowledge their Creator, in the first place there are the Moslems: they profess to hold the faith of Abraham, and together with us adore the one, merciful God, mankind’s judge on the last day. Nor is God remote from those who in shadows and images seek the unknown God, since he gives to all men life and breath and all things (cf. Acts 17:25-28 – from Isaiah 42:5), and since the savior [sic] wills all men to be saved (cf. 1 Tim 2:4). Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience – those too may achieve salvation.”

Contrast all that with a popular, doctrinaire 'haredi' version of Rambam; the ‘finality’ of the 13 Principles, the common conviction that “a heretic, is still a heretic” (regarding even unknowing transgression of certain of the ikkarim), etc. From the ‘haredi’ perspective, being Doctrinally correct in thought and deed is synonymous with salvation (many of them believe - but don’t articulate - that it’s synonymous with being Jewish); "it's the thought that counts" or "good intentions" or even "good works" are irrelevant. A haredi person who holds this belief might ask,“If the catholics are honest (by haredi conception of ”honesty”), how can they not believe that all are lost - in this world and the next - except catholics?" Because to be Catholic is to abide by church doctrine – and church doctrine does not teach assured eternal damnation (or eternal non-existence – a common haredi folk doctrine regarding goyim) for non-Catholics!

Kiruv contexts abound with the aforementioned belief, and it’s taught as if it were universal christian doctrine. Regarding the Catholic church, it is precisely the opposite - other historical, mainline denominations share such open salvific doctrines (see Marc B. Shapiro's interesting piece here). Another example of how we look like fools before those who know our error, and when if we aren't telling the truth, we're telling lies to teach Torah. On top of which, the mainline 'haredi' perspective on non-Jews, on the other 999% of humanity, is that if anything, their lives are mere backdrops to Israel and in death they simply cease to exist. How low are we, how far we’ve taken ourselves and Torah by our behavior that the goyim can look at us and our way of life and say that God-Given Yahadut is surpassed in mercy and decency by l’hvdl manmade institutions!!
Whats left to do? Criticize haredi essentialist cosmology? But to be consistant mandates criticizing essentialism as such – which is what Kellner et al suggest we do. Their basis is often a moral one; that teaches of "essential difference" between Jews and non-Jews leads only to ethnocentrism, which leads to racism, mass murder, stealing candy from goyishe babies, etc.
I would rather answer this charge of the consequences of "jewish essentialism" by addressing general essentialism; returning to the Catholic example; “Extra ecclesiam nulla salus”; “outside the church there is no salvation”; sanctification in this life and salvation in the next requires the benefit of the sacraments and divinely-given grace. To actually even cognate the defining differences between true and false regarding the evidences of the Church, etc, one must have received these “Church Militant”[def]-administered transcendental means and Yeshka-Given divine grace, i.e., be Catholic, be fundamentally distinct and transformed in essence (you can’t know without experiencing); therefore in the absence of this essentially metaphysical grace - one is not necessarily culpable; salvation outside the church is by Mercy, which is over all His works, not based on participation in the particular, essentially distinct Relationship shared only by “The People of God”; the excerpts above evidence just this, as one is associated through them and through a general mercy.