that's really funny. according to you and your religion, humans --- and all living (if you could even say "living") things --- are just atoms and chemicals that somehow happened to orient themselves into the right pattern to form machines... multiple times. in that case, EVERYTHING related to life, rights, morality, etc. are ALL opinion-based. that same philosophy could very well be used to ask "why not just let both mother and child die?" or "why not make murder legal?". heck, wouldn't that make everything technically legal since the ones making the laws are the same clumps of protein-balls that we are?
and then Christains come along. let's say everything they say is false. we still give humanity purpose and morality. we're the ones who fight to protect the bodies of people INSIDE wombs from selfish, bigoted secularists who think that comfort and on-paper goodness is more important than human life. even the few standards you claim to have originated in our teachings, no matter how much you loath the thought of it. all that said, what exactly does society have to lose by following Biblical structure in this hypothetical universe? it's not like you have any rights to be violated (we aren't even violating any of your rights in the real world, we simply make you respect other peoples' -- the horror!), so why so passionate about your opposition? is society the god or ruling deity you claim isn't real? or the government? the answer is easy; Atheism is a religion, and all that you've said about how Christians see themselves is EXACTLY how you see yourself. dominant. different. unargueably 'correct.'
so this whole time what you've been trying so say is: Christians are supremastists because they don't submit to your supremacy.