Onesimus was a slave, and he had obligations to Philemon. Refugees usually are not runaway slaves. There is no indication that Philemon was trying to murder Onesimus. That is not the case with many refugees.He also ministered to Onesimus and then told him to go back and make it right. He did not just say ok well you can ignore your obligation and the law because now you are a Christian which is what the average Christian who supports illegal aliens does either by design or in effect.
This is a false comparison.