If this turns into a massive feud between tons of realms, who loses?
Not Astrum. Not Sanguis Astroism.
The losers are the people whose realms would form the battleground (even if they might technically achieve their goals): Phantaria, Terran, Saffalore, Asylon, D'Hara, and the Farronite Republic.
The only strategy available to FR and D'Hara which is rational is to get out of the way and try to minimize the level of chaos in their region: so maybe not actively support the crusade, but certainly not get in its way. D'Hara can't afford to make more enemies, and FR can't really afford to alienate the church. So they may neglect the crusade, but they can't oppose it: not without a larger level of suicidal tendencies than I normally expect from them.
Also, in other news: Hireshmont has been stabbed by an infil again. Hooray.