They might not be able to get 'dominion', but they could do a lot of damage with a 'crusade'.

It is disturbing that it seems to shimmer through that they think the current system is moral and all, but they think one thing wrong with it, that is that not everyone is -basically- indoctrinated. Also it is opposite to definition that a secularism persecutes any religion. What probably happened that they were the ones overly forcing their religion and people got on the defensive.

Maybe they are so afraid trying to stick to their own beliefs, they think forcing everyone to believe the same will make them able to never hear any other opinions.