'We', as in our society. Don't be obtuse.
What do we do with people who come up with opposing moral views? In our society, we let them make their case. If the morality they propose works better for our society than what is currently practiced, they will be able to make their case and persuade us to change our ways.
I'm not being 'obtuse.' We, in our society don't agree on these things. Who is the 'we' whom we believe? (e.g. you don't believe me as to what is moral, because I adhere to Biblical standards of morality. Am I not part of our society?)
Who makes the determination as to which standards work?