Last year, during the latest military flare-up of the Israeli-Palestinian conflict, hundreds of people took to the streets in German cities chanting pro-Hamas slogans and calling for Jews to be gassed. Here's a video taken during one of these demos:
If you were expecting white German skinheads, you were disappointed. This was a demonstration from the far-left 'Solid' group, and as you can see, the majority of the demonstrators were not ethnically German. At about the 1:30 point, a man speaks into the camera in German, with a strong foreign accent. The anti-Israel demonstration is running toward a pro-Israel demonstration looking for confrontation. The man notes this 'isn't good', but has to happen since 'the Jews are insulting us'. 49 people were charged with inciting racial hatred for chanting anti-Semitic slogans during this demonstration, but charges were later dropped (g) against 45 of them.
There is, of course, anti-Semitism among native Germans. But I can tell you from first-hand experience, there is a whole lot more, and more virulent, anti-Semitism among residents of Germany who immigrated from Muslim countries. I have had dozens of conversations with recent immigrants from Muslim countries (often during German as a foreign language courses) that made my hair stand on end. Of course anti-Semitic attitudes are not confined to Muslim nations, but they are particularly common there. This should come as no surprise, since high-ranking leaders of the Arab world, especially, are notorious for embracing the Protocols of the Elders of Zion as truth:
The exception to [the universal consensus that the Protocols are an anti-Semitic hoax] is the Middle East, where a large number of Arab and Muslim regimes and leaders have endorsed them as authentic. Past endorsements of The Protocols from Presidents Gamal Abdel Nasser and Anwar Sadat of Egypt, one of the President Arifs of Iraq, King Faisal of Saudi Arabia, and Colonel Muammar al-Gaddafi of Libya, among other political and intellectual leaders of the Arab world, are echoed by 21st century endorsements from the Grand Mufti of Jerusalem, Sheikh Ekrima Sa'id Sabri, and Hamas, to the education ministry of Saudi Arabia.
[A]bout 40 Muslim weekend clubs and schools in the UK [are] using Saudi textbooks that, among other niceties, describe Jews as descended from "monkeys" and "pigs", denigrate nonbelievers, advocate killing homosexuals and refer to the "reprehensible qualities of Jews".
And Syria is one of the very worst offenders. Syria's current leader, Bashar al-Assad, has said:
'We must therefore speak about the street and not get bogged down in analyzing people. We say the [Israeli] Prime Minister is racist, the government is racist and the army is racist, but when we come to Israeli society, we are speechless. What is the sense of this? Everything that has already transpired is a result of Israeli society. It is a society more racist than the Nazis. Everyone says this in closed meetings. Every Arab citizen says these things. We represent the Arab world and it is therefore natural that we say what they want us to say and in a manner that will express the conscience of the Arab citizen'.
During the Pope's  visit to Syria, the President delivered a speech in which he referred to Israel thus: 'We hear them destroy the principle of equality while they speak of Allah who singled out their nation from other nations and we see them damaging the holy places to Islam and Christianity in Palestine … They are trying to destroy all the religions' monotheistic principles, according to the same mentality with which they betrayed Jesus and tortured him, and according to the same mentality with which they tried to kill the prophet Muhammad'. (emphasis added)
In mid-2014, a UN school for Palestinian refugee children in a refugee camp outside Damascus posted these cartoons to Facebook, celebrating a recent trend of Palestinians killing Israelis by running them over with automobiles.
There are thousands of examples of anti-Semitic indoctrination like this from all over the Muslim world (although not only the Muslim world, of course), and Syria is always near the top of the list.
It should come as no surprise, then, that Syria's once-thriving Jewish community has scattered, and that there are only 22 Jews left in Syria. So, as we welcome hundreds of thousands of random Syrians who happened to make it to German soil, we should keep in mind almost all of them were raised in a virulently anti-Semitic and anti-Israel political climate and educational system. And, as we saw in 2014, the mere fact of relocation to Germany does not automatically render every immigrant into a benevolent, tolerant person. I wonder if anyone is giving any thought to this?
One of the advantages of controlled immigration is that you have a better chance of weeding out people who are going to cause trouble in your country, for instance by chanting openly for your fellow citizens to be gassed to death. First thing we need is a border fence to stop the spectacle of masses of humans hiking across Southeastern Europe. Refugees should be screened where they now are, and if accepted, flown humanely direct to the country that has accepted them. There should be refugee-relocation centers in Syrian camps right now to screen potential refugees for relocation in Germany. They should have fluent Arabic speakers on staff. Preferably fellow Arabs, to increase the likelihood of honest answers. I would ask prospective Syrian refugees the following questions:
1. Are you aware that Germany has a large and growing Jewish population?
2. Are you aware that the Government of Germany has a close relationship with the State of Israel?
3. Do you believe that the Nazis murdered 6 million Jews during the Holocaust?
4. What is your personal opinion of the Jewish faith?
5. What is your opinion of the State of Israel?
6. Do you believe that Jews drink the blood of Christian children?
7. Do you believe that Jews have a secret plan for world domination?
8. How would you react if a neighbor moved in next door who was Jewish?
If the prospective Syrian refugee gives the 'wrong' answer to 2 or 3 of these questions, their application will be denied. They can apply to another country for asylum, one that is more in tune with their ideas. Germany is not obliged to take in all of the world's refugees, and doesn't need to import any more anti-Semites than it already has.