Is it ethical to refuse accepting Syria war immigrants?

The question is slightly wrong. There is no ETHICAL question about a country refusing access to a MIGRANT. Migrants can be allowed or refused entry according to the laws of the country concerned.

I think the question refers to REFUGEES.

A refugee is defined in the 1951 Refugee Convention as a person who has a well-founded fear of persecution in their home country. http://www.unhcr.org/pages/49da0e466.html

There are some interesting FAQs here http://www.unhcr.org/en-us/about-us/background/4ec262df9/1951-convention-relating-status-refugees-its-1967-protocol.html

But does living in a war zone count as persecution? I have tried to find out, it is very difficult. The point being that the difference between “migrant” and “refugee” is often blurred. Europe has of course seen many awful wars. If the 1951 Refugee Convention had been in place during WW2, would civilians from occupied Holland, say, have a legal right to be viewed as refugees and therefore be taken in by (neutral) Switzerland? Would it make a difference if they were Jewish? Would civilians be regarded as refugees only when the fighting was going on?

In any case, if living in a war zone counted as being a refugee (I don't know), you can see that Switzerland would have been swamped. What would Switzerland have done in such circumstances?

Now change "Holland" to "Syria, Somalia, Libya.." and "Switzerland" to "European Union, USA..."

Maybe it all depends on numbers? But the potential number of refugees (if the definition fits) is huge - and beyond the abilities of recipient countries to cope?