Post-anything means that thing has failed and was not what it was supposed to be. Post-Marxists even try to claim that they are not Marxist, for example, though they retain the core.
The core in this case, however, is difficult to maintain, because the core of Christianity is the idea of something being beyond time and matter, but the goals of a post-Christian faith are to focus more intensely on those problems of time and matter.
That they are just getting started means that they don't even know what it is supposed to be, just that it shouldn't be what it was or what it even is right now. It needs to be taken over, its symbols, its artifacts, its history, its concepts, its peoples, and to have all such things consolidated into the process of seeking that which has not yet come to be.
But not only that, we are associating it with Christian Nationalism. That means that it is White Christian Nationalism. It also brings in male privilege, which is another way of saying Patriarchy - so we are bringing in the standpoint epistemology of critical feminist theory, which is a Marxist theory of sex. It steps it up a notch and says "obsession with regulating sexuality", by both cementing the feminist critique of saying that women can't have an identity of their own because it is defined, in this clause, by the regulation of their sexuality, but it also opens the door to making this about queer liberation, which is certainly to come more explicitly in the writing.
Overall, we can see that this all means Fascism. We are placing all of the identifiers which reference the popular view of Nazism, the commonly understood formulation of Fascism (very few people have actually read about Fascism proper). This is done because it is now patriarchal nationalism on principle of race. This means that Christianity itself is represented as Patriarchal Nationalism on principle of race, and this is just the beginning of the article. A controversy is introduced and a dialectical inversion is being formed as a proposal to the reader.
Of course, what's really happening here is something that has happened before. The idea of humans having beliefs and thoughts of their own - having their own capacity to discern and contemplate in pursuit of truth - this is something which conflicts with a state which makes declarations about what is true. The state can't simply function to an extent of saying that it doesn't know something. It only makes statements in a manner which implies certainty or, at the very least, congruence with the highest authority on a particular matter. The idea that there could be a populace which is performing its evaluations outside of the pool of expertise recognized by the state is offensive and threatening to the state apparatus.
As a state becomes increasingly authoritarian, it needs for its subjects to be perfectly compliant and maintaining a position which does not and cannot challenge the positions held by the state. As the driving factor for pursuit of truth is in man's contemplation of meaning and purpose in the world, it becomes clear that interest should be taken in those activities which allow for man to undertake the most explicit pursuit of truth under a setting without constraint of subject or procedure. Religion, philosophically-driven dissent, activism, psycho-naught i-cal exploration and similar are all activities for which the state isn't necessarily expected to be present, perform audits or provide direction (at least under normal circumstances and as per the precedents of our modern era.
The interfaith effort allows for the truth-seeking aspirations of individuals who happen to be involved with pursuit of an understanding of the world and their faith to be placed in an environment of ambiguity, where the presumption that participants are each in pursuit of the same will lend a false sense of security insofar of accepting declarations in the environment which are purported to be truth-oriented.
https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1271&context=socs_fac