The article failed to make its points.
The word unAmerican is used by people to describe things they themselves feel passionate about. But it doesn't mean much of anything. Trump's supporters would use it in reverse.
The key assertion seemed to be that Trump's new travel ban will make America less safe. But it didn't say why.
You can easily argue that stronger vetting and reduced volumes of visitors make America safer. Presidents are elected to make such decisions.
For myself, I think Obama's see-no-evil stance was untenable. Leaders will try new solutions. Some will work. Some won't.
My guess is this EO will proceed through the courts successfully. And it will prevent many perfectly decent people from travelling to the US. Perhaps it will also capture one or two bad actors. I don't know.
But it won't solve the problem of homegrown jihadi terrorism. The lone wolves are going to be with us for a good while.