Here's the first definition I find when I search for it : https://www.dictionary.com/browse/secularism#:~:text=definitions%20for%20secularism-,secularism,no%20place%20in%20civil%20affairs

noun:
1. philosophy a doctrine that rejects religion, esp in ethics
2. the attitude that religion should have no place in civil affairs
3. the state of being secular

Can you at least see why I, and several other people, are confused?