The purpose of separation of church and state is not to create a secular society. The purpose of separting the church from the state was to avoid creating a state church like the Church of England.
In response to your right to peruse life, liberty and happiness.. Well, your notion of life, liberty and happiness is infringing on my notion of the right to life, liberty happiness. So what you are saying is that your ideas if morality, marriage, family are superior to my ideas of marriage, family, etc. Can I not be an atheist and not believe in gay marriage? Can I not believe in God but still reject abortion? Don't you see the problem? You are saying that your beliefs are better than mine and that I should believe what you believe. Isn't this the same thing that "religious" people say? We are both being narrow minded.