The standard for virtue and vice is determined by what Paul lists in his letters as works of the spirit or works of the flesh. So homosexuality and witchcraft are condemned as sins because Paul lists them as bad fruits, so while it is true that just because the Torah prohibits something this does not mean it is automatically prohibited for Christians, we do have New Testament standards to live by, and these standards are built upon the moral law rather than ceremonial. We can distinguish between ceremonial and moral aspects to the law through this criteria.
