An atheist forum would be the same, but the whole point is that mostly they would not debate religion as theism vs. atheism.

People would be more likely to be anti-clerical than atheist, hating the church as an institution in society, that spreads conservative ideas and props up authoritarian regimes.

On the other side, people would be talking about "Christian values" not about faith or belief. Not even belief in belief (of factual statements), but belief in that the values, the norms, the prescriptions are useful. They would also talk about identity, like a "national christian identity"