We live in a nation where the majority of people are Christians. Christians are the most outspoken in this country, when it comes to religious people. Therefore, it always seems like Christians are the ones trying to push their agendas (or the ones opposing agendas that they don't agree with). It's the Christians who rally together opposing same-sex marriage. At least, that is what I tend to see. This goes the same for other hot button issues.
Denying the existence of something means that you have to believe it exists in the first place? Please. Let's say that you don't believe aliens exist. Does that mean that you admit they exist because you are denying that they exist? That makes absolutely no sense at all.
I join these forums for discussion. I learn a lot from the intelligent Christians who post in these types of forums. Since, like I said earlier, Christianity is the most common faith in the country that I live, I find it important to understand as much as I can about it.
I am a member of a few different atheist forums. We talk about issues that affect our lives, philosophy, morality... actually, we talk about the same things that you talk about for the most part.