Refugees

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“Some have severe mental health problems resulting from broken families or parental neglect, exposure to violence in their home country, and a traumatic experience coming here illegally.” – Jessica Vaughan, Center for Immigration Studies

Illegal aliens that go on to commit crimes other than ICE violations are now called, refugees.

If refugees are dangerous (for whatever reason, even psychological), then why are they being admitted?
If admitted, are they being isolated and treated before joining the general population?

Or, could there simply be a culture clash where certain behaviors are typical and accepted in some countries?