Explain, briefly, why some people are prejudiced against Jews

When I sat GCSEs, a perspective-distorting 17 years ago, I don't remember any questions like this:

Explain, briefly, why some people are prejudiced against Jews (AQA Religious Studies 2012)

And it's got everyone very irate. I'm disappointed in the Secretary of State who has claimed that it shouldn't have been set because it 'suggest[s] that antisemitism can ever be explained, rather than condemned.' I've always had time for Mr Gove's pursuit of academic rigour, if not in agreement of this methods, but I'm now thinking I have overestimated him. There is transparently no tension between explanation and condemnation and that kind of reaction makes me think he is thick. In fact, I think that kind of reaction makes me want to have them set the question. Understanding why hideous things happen helps us stop them. I'll return to whether it belongs in a GCSE below.

For the record, and off the top of my head, I'd suggest the following answer:

1. Let's assume by prejudice we mean irrational hostility, not a response to genuine enemies. For example, I would suggest the Philistines were not 'prejudiced' against the Jews, but rather fighting a war (see 1 Samuel 17)
2. Said prejudice is probably borne out of 'problems at home', perhaps fear or poverty, i.e., they're lashing out at a target (I simplify, but we brevity has been stipulated). As GCSE students won't have studied any history, they'll all talk about the depression and the Holocaust, but they could also point to other examples, perhaps the Great Persecution in an insecure Empire Galerius 
3. At which point you might ask, why the Jews. And there are two ways of tracing this: said prejudice is old, and modern antisemitism draws directly on historical hostility to Jews. There's lots of this, but I think it can squarely be rooted in the Jewish nations resolute non-identification with the establishment in antiquity. The Jews rejected the Emperor-cult in Pagan Rome and obviously the Christian identity that followed. That's bound to make you unpopular. Of course, you could suggest that the modern Islamic antisemitism also owes something to the position of Israel and have a useful discussion over which came first, drawing in the career of the Grand Mufti of Jerusalem
4. The second point to trace is extraordinary tenaciousness of the non-geographic national identity of the Jews. many groups draw hostility but national hostility tends not to last if they don't. I don't have views on the undesirability of Goths as neighbours (OK, I do, but that's rare - they'd be fine). The Jews don't, and they're exceptional in that respect. Unfortunately this functions as a multiplier effect for prejudice for much of their history, which is unfortunate. 

Of course, it's actually much more complex than that, but I think it's pretty interesting, and important. I'm not sure how useful it is to ask 16-year-olds as they don't have the breadth of knowledge and understanding to say anything meaningful. I don't think they should be taught the Nazis and the Holocaust in history either, so I would be very happy if they objection was that this stuff is hard and complex, so we should delay it. However, it's not. The objection seems to be that the world is unpleasant, so we shouldn't examine it. And that's pathetic.