No one outside the Obama administration and the Trump administration, not the judges trying to second guess nor the demonstrators, know why those 7 countries were put on the Homeland Security list in 2015. It's not about Islam, or another 43 countries would be on the list. It would seem prudent to wait. That is, unless you voted for Clinton and just hate Trump.
I see a lot of "we are all immigrants" signs on FaceBook especially from those who just weeks ago under Obama were saying "we" stole the land and enslaved Africans. But there were always rules. My immigrant ancestors had to swear allegiance to King George II of Britain before selling everything or their labor to pay for the journey, and then there was no help from the colonial government of Pennsylvania only from whomever purchased their labor or others of their faith.
Michael Smith had a thought of merit: "It seems to me that Trump has set up a situation where the people who oppose this Executive Order are going to have to explain in court why this condition is unconstitutional now and it wasn’t unconstitutional in 2015 when Obama signed the Visa Waiver Program Improvement and Terrorist Travel Prevention Act of 2015 in to law. It will also have to be explained to the American people why constitutional rights are extended to non-citizens. I think the challenges may well have the effect of unveiling the true political bias of our judiciary and the feckless nature of our legislature. Trump is making good use of Alinsky's Rule 4: “Make the enemy live up to its own book of rules.”