I think that casts serious doubt on God’s omnipotence. Is our almighty God beyond making an alternate plane of salvation for non-Catholics?
If we look at Islamic history it was Jews and Christians had protected status as monotheists. This status was also extended to non-Abrahamic, non-Muslim communities that nevertheless had some monotheistic elements – such as Hindus in India and Zoroastrians in Persia. Furthermore, it is my understanding that warfare has strict limits in Islamic law.
[2.62] Surely those who believe, and those who are Jews, and the Christians, and the Sabians, whoever believes in Allah and the Last day and does good, they shall have their reward from their Lord, and there is no fear for them, nor shall they grieve.
“Allah forbiddeth you not those who warred not against you on account of religion and drove you not out from your homes, that ye should show them kindness and deal justly with them. Lo! Allah loveth the just dealers.”
“…and nearest among them in love to the believers will you find those who say, ‘We are Christians,’ because amongst these are men devoted to learning and men who have renounced the world, and they are not arrogant” (5:82).