The "we'll turn away a whole group of refugees because they come from a war-torn area and some tiny fraction of them might be hostile" was used exactly during WW2 to say no to Jews, and the same argument is used now to turn away refugees from Syria.
The opposite situation was the Interahamwe who had just committed genocide in Rwanda, and skipped over the border to Congo, only to be housed and fed by international aid organisations. They were fleeing, so they must be poor refugees!
