NS,
To an extent, but the fact remains that academics will generally set out their reasoning: "because X, therefore Y" etc that the rest of us can address with reasoning of our own. The result is either, "you're wrong because of a flaw in your thinking as follows so I disagree with your conclusion", or, "I cannot find a flaw on your reasoning so I must agree with your conclusion".
Contrast that with, "my faith tells me X" and how else can someone respond except with a, "so what"?
As for the constituencies of Bishops, I guess to an extent footfall in churches on a Sunday is a kind of mandate but a more tenuous one I'd say than that of someone elected on the basis of a manifesto.
Except the initial decision here in terms of what should happen is not anything that a moral philosophy professor has any real expertise in. And us just making any such decision on their subjective opinion. As to setting out their arguments logically, depends,I've seen good ones and bad ones, and that applies to moral philosophy professors, other academics and religious representatives, many of whom are or have been academics. The arguments though at base on morality are based on personal opinion. As already pointed out this sort of take on morality, is not what is taught and studied in moral philisophy.
Any good MP prof would, I suggest, address any such questions hypothetically laying out the if you took a certain moral stance, and laying out a variety of them, that one might decided more likely one thing or another in this case. They would not argue for a particular decision as they should realise that that would not be appropriate for them.