People with those beliefs don't believe people who don't have the same imaginary friend are deserving of being treated like humans.

If you kill me for being a heathen you've taken away later opportunities for me to convert. Not just a murder but eternal damnation based on your human judgement of me. The hubris to think that is your job when you believe your god is all knowing and all powerful. Doesn't that mean it is gods will I'm here and you've undermined him?