As Christians we believe our souls are our minds, our wills, our emotions, created free, in the image and likeness of God.
What exactly do you think you are if you’re not a soul endowed with a mind, a will, and emotions?
An accident of stardust...
So... what moral claim could one accident of stardust make on another?
What right would one accident of stardust have to tell another one that it is “wrong”?
Chemical reactions in an evolved portion of the anatomy makes up the mind and will. Emotions are primarily the result of lower portions of the mind (and even the body, and just genetic code) manipulating higher portions of the mind. The genes want to perpetuate, the body has a whole section devoted entirely to genetic immortality, the lower mind makes us fall in love so that we can acquire a breeding partner.
It’s all pretty straight forward stuff actually. Pretty well explained these days backed up by experimentation, and manipulable through drugs (both with and without supervision). Religions were designed by pre-scientific people to explain things they didn’t understand. But a lot of that stuff is very understandable now. There are identifiable chemical reactions to these things now, we can look at a brain scan and say “this guy is happy, this one is depressed, this one is in the early infatuation stage of love, this one is in the long haul comfortable partner stage”. It ain’t tough, and it ain’t mystical.