You wrote, "If we apply God's laws to this then if aliens are illegal then so to are residents." What???
Christians can treat and should treat all of God's people the same, however God places our government over us to keep order in society.
That's the difference between law and gospel. Christians should always grant the gospel. God showers His grace upon us as sinful people and we should do the same to all of His people.
However there is also the law which requires punishment for wrongs. That is what death is all about. Jesus came to save us, but death is still the consequence of our sinful selves.
While by God's grace we are saved we still have the consequence of death before eternal life.
It is against the law for Illegal Immigrants to work in our country. If they want to proceed legally to come in and work that avenue is open to all. However just because we are to treat all of God's children with the grace He has afforded us does not meant that there is no consequence to their disobeying of our laws.
THe bible says it is immoral to make them illegal. I'm sorry if you don't like that but its the truth.