We Never Know
No Slack
One key difference here is that no human beings are harmed by removing the 10 commandments or a manger from a courthouse lawn.
The U.S. is a signatory to the Universal Declaration of Human Rights. Regardless of their immigration status, we are duty-bound to respect and honor their rights as human beings.
We are duty bound to take care of legal citizens which we aren't doing a very good job of.