It's supposedly quite easy these days to get fake Syrian passports in Turkey (and other places probably as well). It's known to the authorities - and not only US - it is also known that the Syrian passport is easy to counterfeit.
There are scores and scores of folks travelling to the US every day. These were just some of those. They were not refugees. The refugees that are coming to the US are going through totally different channels.
I really don't think you should be this worried about the refugees. I understand the fear, believe me I do, but you can't lose your humanity because of fear ...