Thank you for sharing your point of view. Please, let me share my thoughts on this.
1.) I think your focus is a bit too much on Syria, there are also refugees from other countries. Still many from Syria, but far more from other countries, e.g. Afghanistan and Irak. Here a statistic from 2017, in German language.
2.) Why Syrians? We cannot that easily ‘select’ which we take. There are rules on the one hand (e.g. Geneva Convention on Refugees) and ethical mindsets on the other (many old Germans themselves were war-refugees) — hence, refugees of war receive broader approval. And additionally, lots of people in Germany want, that the refugees shall return to their home country as soon as war is over; see for example the debate called “Sicheres Herkunftsland” (safe origin country) and an ‘okay’ to this agenda is somewhat the political mainstream. Syrian regime-change-negotiations are another topic, I won’t touch that now.
But please realize, that anti-Semitism of refugees is not the main reason of the conservatism against refugees here. It is about economical and security reasons. And then again, in some cases it simply is racism and culturalism (which also might turn against Jews again one day, and already is, as you also mentioned). Anyway, some anti-Islamist tendencies (not only refugee-related!) spread into mainstream and start to look like the anti-Semitic agitation of the early 1930s in Germany.
3.) Germany in 20. century does not only mean Holocaust, but also imperialistic interests (two world wars) and idiological division during cold war’s bloc alignment which itself lead to quarrel between people of old and new states of Germany.
Furthermore, after the world wars, our country was (and is) involved in shady arms deals and is involved in wars breaching international law.
What does this mean to the zeitgeist? It is getting more radical, racist, nationalistic, egoistic, chauvinistic. A bad trend for all of us.
Somehow one has to break the cycle. Otherwise we will go on with repeating the errors of our ancestors.
But this is just the point of view of an atheist, a somewhat leftish game developer, born in Eastern Germany in the 80s.