Justinian reconquest of Italian Peninsula did not result in a permanent war against Catholics, vice versa. Instead, it resulted in a period of Byzantine Papacy with mostly Greek popes.
The -200 Religious Aversion modifier is quite ridiculous, especially if the attacking side is either Orthodox or Coptic.
It'd make sense if Muslims took over the city, but even then, Europeans were preoccupied with their own politics after the crusades failed. France was willing to cooperate with Ottomans just to contend against Austria. The aversion should either be workable or disappear after some time.