If there is a message on this subject here, it is the opposite. We can criticize across domains and use a mixture of judgments. Metanarratives generally kept information incompatible with the decided parameters of a discipline outside. The metanarrative of scientific objectivity could keep religious sentiment from mattering on the whole, when that was necessary or convenient. People mixing the two were off-topic, even if they were right. 'Science' as a whole could simply ignore them, even if individual scientists engaged. And to a great deal religion could ignore science, too.
It should now be clearer that it is reasonable for people to criticize participants across domains.
The merger of different threads of the study of History and Literature is where this is most striking. The metanarrative of 'nation formation' in US History, or some overarching theory of the Literary Canon is no longer immune from the protestations of marginalized groups once consigned to a second tier of specialists. It is no longer OK to tell just the story of the top-level decision makers who ultimately succeeded (at controlling the world or getting texts disseminated), or who influenced those who would, because we had defined the subject that way. Perspectives unrelated to that are now a real part of history and literature as disciplines. This makes for a lot less clarity, and drives students away in droves, but it lends a greater richness to our understanding of the world.
We have always had little wars between metanarratives, a la Scopes, where, for instance, Science defended itself against Religion, based upon unwritten, but very powerful ground-rules, or the two made peace in ways that then became unwritten rules. These are driven by metanarrative.
But we now have religion or business telling science that certain determinations are simply unacceptable, not on a scientific basis, but in the terms of those disciplines. They can demand that global warming must be questioned more deeply than other scientific narratives, because of the consequences in those domains, not science, and they call for better proof.
Or we can bend things the other way, asking for less proof: We integrate Chinese and Western medicine despite their inconsistency. This holistic thinking creates 'new agey' assertions of pseudo-scientific facts, and people are open to them for reasons unrelated to what medicine knows, because they experience them working. They do not have to wrap themselves in bad science anymore. If something is 'natural', it is simply good, in the minds of many, on a basis unrelated to nature. And we do not have to choose between Science and QiGong. We can cross between them more freely as individuals and not be cowed by either camp.
Individual narratives crowd out competitions between metanarratives. Take your example of abortion. We do not accept the walls of separation between medical decision making and social mores, and we end up devolving these decisions more and more down to an individual narrative -- given pregnant women -- rather than trying to resolve them with high-level rules negotiated between the metanarratives of Medicine and Morality.