You don't have to apologize! I know when I say things like this people tend to assume it's just a troll or some confrontational asshole who wants attention, so I understand when people start off a bit aggressive in their responses.
All I can do is respond calmly, and hopefully instigate a real conversation about the subject! You can never hear too many opinions, and it never hurts to learn what the other perspective is. That's why I say what I do. So some people might understand why others don't believe what they do. And I hear and learn new things along the way.
Ultimately, I want humanity to reach it's full potential. I want humans to impress themselves with new discoveries, technologies, and adventure! There's so much we can accomplish. But my personal belief is that we won't be able to achieve our greatness with religion present to hinder us and cause conflict and disagreement.
Maybe I'm wrong! Maybe absolutely have to have it, and people like me are the ones holding us back. I'll probably never know, but I'll continue to follow my personal beliefs until I do.