The 61-year-old, who was baptized on March 22, 2008 by Pope Benedict XVI himself, wrote in the Il Giornale that his relationship with Catholicism ended with Benedict's resignation.
"The 'papolatry' that has inflamed the euphoria for Francis I and has quickly archived Benedict XVI was the last straw in an overall framework of uncertainty and doubts about the Church."
Regarding the Church's stance on Islam, and why he has chosen to leave:
Allam, who has called Islam an "intrinsically violent ideology," said his main reason for leaving the church was its perceived "religious relativism, in particular the legitimization of Islam as a true religion."
"Europe will end up being subjugated to Islam," he warned in Il Giornale, unless it "finds the courage to denounce Islam as incompatible with our civilization and fundamental human rights," and to "banish the Quran for inciting hatred, violence and death towards non-Muslims." Europeans also need to "condemn Sharia as a crime against humanity" and to "stop the spread of mosques."
Allam still considers himself Christian, just not a Catholic.