Why do Christians quote scripture when debating non-believers?
While I agree with you, we have to be somewhat fair. The Bible is a guidebook for life, and many Christians believe everyone would benefit from it if they followed scripture. In other words, you use what you know. I don’t think we can expect a Christian to use anything but what they believe to be true. With that being said, I do wish more people would try to use secular reasoning in approaching everything unrelated to religion. It would only be fair to everyone. But we’re a long way from every human being concerning themselves with fairness.