“Garbage in, garbage out” is a decades old axiom in computer science, describing how when computers fed nonsense input, will dutifully spew out nonsense output.
It also applies to religion; a logical construct based on false premises, such as a moral arbiter god, inevitably comes to erroneous conclusions, such as homosexuality being a choice, or that marriage can only be between men and women.
So we are seeing in the fallout of the Irish marriage referendum. This result is a huge milestone in the progression of society towards pluralist secularism and away from theocracy.
The Catholic conservatives blame the church for having shifted away from its core principles (the garbage in) causing people to change their attitudes away from homophobia (the garbage out) and become not just accepting but enthusiastic for same-sex marriage.
It is the adherence to these core principles that drove people away in the first place. The churches have lost the factual arguments (biology tells us sexual orientation is not a choice, and history tells us marriage has changed constantly), and consequently, are losing the moral ones.
The liberal theists, being less literal, understand better that attitudes shift with time. They know, perhaps subconsciously, that the program needs an update, but are fond enough with other bits of the code that they stick with the project.
We as atheists are, for the most part, aware that morality is not absolute. The Zeitgeist changes and always has done.
Colin Morrison, Atheist Northern Ireland