Secularism is not irreligion. It is not throwing away holy books.
Secularism means to disable those who want to oppress and use force in the name of religion.
one of the major tricks marxists use is to change the perceptions and definitions of words. For example in the west a patriot or a nationalist has been turned into fascist and racist. The Islamists used the same trick with Secularism, they fooled the people into believing that secularism means atheist and against religion. Without secularism, in a country like Turkiye you will end up with religious tyranny. Like what happened in Iran. Secularism actually guaranteed your freedom to believe what you want to believe, to worship who you choose to worship.