Everyone in the Illuminati is a Christian. Lucifer is Jesus. Jesus is Lucifer. He's the light of the world. It's a word game.
They just need you to do a baptism ritual so that they can enforce Canon law over you. According to the Cannons there are 4 types of people:

1) The unbaptized = infidels (non believers) The church can't punish infidels for non belief, since they're not in the body of christ, aren't dead and ressurected in christ etc.
2) Baptized people who believe in Roman Catholic dogma and adhere to it. These people are orthodox Catholics. They're left to be guided by the sacraments and pastors etc.
3) Baptized people who don't believe all of the Roman Catholic dogma, or make pronouncements against it. These people are deemed heterodox (heretical) Catholics. These people are to be admonished and re-educated. This is the majority of Lucifer is god illuminati type people. Lucifer is christ christ is god, they just are heretical in the rest of their beliefs. It is no murder to kill a heretic.
4) Baptized people who reject the entire religion, or switch religions. These people are deemed apostate. Apostates are to be put to death. This includes all atheists. Anyone in the Illuminati that is atheist, and most Illuminati baptized people that are following non christian religions or religions so radically different that they bear no resemblance to Christianity. These are the targets of the inquisition, which is now days prosecuted with wars, and very rarely on case by case tribunals, unless you really piss them off.

TL/DR : End of story 95% of the population of the world are secretly baptized Catholics.