Another anon! Yay! I think what this is boiling down to is simply: you are atheist (correct me if I'm wrong, I thought you've said that before) and the people you are talking to are Christian. The fact that you don't agree with us is completely fine. However, I don't understand how you can't respect Christians who personally don't believe that gay marriage is right, understand others don't have the same belief system, and stay out of the matter...?
All I’m saying is that your belief system is intolerant of other people. This is a statement of fact, not a sign of disrespect. You have to either accept this thing about your worldview or change it.
Intolerance like your’s is the reason that LGB kids are 4 times more likely to kill themselves than the national average, so I don’t feel like there’s any particular reason I should just “stay out” of it.