Progressives, in a state of full-blown Trump Derangement Syndrome are incapable of getting facts straight where Trump is concerned.
This executive order is NOT about choosing nations that are Muslim Majority. It is NOT about choosing nations from which terrorists have come in the past. It is NOT about choosing nations supplying funding to terrorists. It is NOT only about choosing nations which have terrorists in them today, that might come to the US.
It is about choosing nations that can't, or won't, supply adequate information that can be used in vetting. Here is where it says that in section 3b: "The Secretary of Homeland Security, in consultation with the Secretary of State and the Director of National Intelligence, shall submit to the President a report on the results of the review described in subsection (a) of this section, including the Secretary of Homeland Security's determination of the information needed for adjudications and a list of countries that do not provide adequate information, within 30 days of the date of this order." [My emphasis]
That is why the list of seven, that was originally put together under Obama, was chosen. Here is what CNN reported on the list of seven: "In December 2015, President Obama signed into law a measure placing limited restrictions on certain travelers who had visited Iran, Iraq, Sudan, or Syria on or after March 1, 2011. Two months later, the Obama administration added Libya, Somalia, and Yemen to the list,in what it called an effort to address 'the growing threat from foreign terrorist fighters.' "
If a person is not a citizen of the United States, and has not been granted legal permanent status (green card) then they do NOT have any right to enter the country. The executive branch has been given constitutional authority over entry into the country. It is appropriate for the president to deny entry for anyone who comes from a place with significant terrorist activity if they cannot be vetted because that nation isn't able or willing to supply the needed data.
I hate the way laws (or executive orders) are written today. They are full of useless legaleze, mind-numbing detail, a thousand times too long, link to other laws and documents ad nauseum, and often just cannot be followed. I agree with Rand's disdain for non-objective laws. But this executive order, however poorly written, however non-objective it is in style and format, has an objective intent based upon national self-defense.
Open border people object to any kind of restriction, but if asked, "Do you believe that terrorists should be allowed into the country?" they will either waffle, or say, "No" but then have no idea of how to keep them out. Or they will say something like, "There is no way to guarantee terrorist can't get in" or "This doesn't address home-grown terrorists," or some other deflection from an attempt to say what should be done to reduce the chances of terrorists coming in.
Saudi Arabia (or at least members of the royal family) has long been (and may still be) a source of terrorist funding and an active exporter of jihadi ideology, but it doesn't meet the standards the executive order lays out for suspending visas until they can determine adequate vetting procedures.
But here is the real point. Progressives are focused on only one thing: undermining Trump for the purpose of regaining control for themselves. They attack Trump on this or that specific, they lie, they distort, they make fake news, but their hatred is due to his effectiveness in thwarting their quest for power. They had Obama and they felt like they were so close to transforming the nation... They didn't see that their policies and political correctness and condescending elitism were generating enormous dislike. It came as a shock that they lost - even with as flawed a candidate as Hillary.