The difference is, MillyMolly, that if you are talking about the experiences that the Russian or German Jews had the comparable people in Syria would be the Christians and Yazidis, but there seems to be very few of them and there are reports that they are attacked as they try to travel, in the camps or on boats.
If Christians or Yazidis moved here, like most German or Russian Jews I would expect them not to go back to a place where their fellow countrymen had turned on them and wanted to kill and destroy them for their religion, of course not.
But the vast majority of these migrants are exactly the people who are responsible for the violence in Syria. Muslims. It's just not comparable because they are not the persecuted group, they are the persecutors.
As a comparison, it would be like before WW2 us encouraging mass immigration from Nazi Germany as long as people professed to just be 'moderate Nazis' who were just in favour of a bit of book burning and Jew bashing but weren't very keen on the whole holocaust thing (which in reality is what most Germans were). We certainly wouldn't have won WW2 if we'd done that.
Christians are largely accepted to be the most persecuted religious group in the world right now. And it's Muslims doing the persecution.
I think anybody who doesn't realise that sort of violence is being imported here is unbelievably naive.