This amounts to a non-religious perspective that is informed by a deep personal familiarity with the history and beliefs of Christianity, and by having several close Jewish friends, one a rabbi, with whom I've had many delightful conversations.
I would first note that on a personal level, antisemitism baffles me in a way that makes me wonder if I missed the memo, so to speak. Judaism is the very source and origin of both Christianity and Islam. How then can anyone from those faiths disrespect that which gave birth to most of what they believe about the very nature of the universe and their roles within it? I just don't get it, either intellectually and most certainly not emotionally.
Yet at another more abstract level, I think I do understand part of what is going on. Most of us go through our lives feeling like we have been cheated in some way, perhaps by our situation, or perhaps by those who raised us, or just by people in general. Not many of us get to have such perfect and gilded lives that we never have the desire to think "why did this happen to me? why is my life so unhappy?"
Once such questions arise, everyone is forced to deal with them one way or another. Unfortunately, even within religious faiths that teach many aspects of how people should treat one another, the incredible importance of how we deal with our own perception of unfairness is often simply overlooked. We choose without realizing it, often simply by imitating those around us.
One choice is to realize others are suffering also, and then asking, "I wonder if there is some way I can help others?"
At the other end of possible responses is this question: "I wonder who is to blame for my troubles?"
These are both answers that are self-reinforcing. If you try to help others and succeed, most people find it an experience that is astonishingly rewarding, often in spite of all expectations to the contrary.
If you choose instead to look for the real source of your troubles, you always will. And the strange thing is, when you find it, it will always look like some kind of strangely distorted reflection of yourself. Everything you don't like about yourself somehow becomes a part of this thing that you have chosen as the source of your problems. The more that happens, the more certain and firm you become in your belief that "There is the source of all my woes! There is the reason why I am so cruel to others, so hateful to my own children, so prone to failure in all that I do! If only that was not around, I would be so much happier with myself, and so much less miserable!" The blurrier the vision of that, the less understood and familiar it is, the easier it becomes to project all of your own failures into it.
"That" doesn't even have to be a person. But of course, too often... it is.
Why are Jewish people so often selected in the Western world to become sources and even the very incarnations of their woes, the sources of everything they see as wrong in the world around them? Because Judaism is the oh-so-close yet strangely baffling relative that most people have never really met and certainly don't understand. They are not strangers from afar, like Buddhists or Confucians or Zoroastrians, who seem so different that they are more like plants and scenery viewed while passing through a garden. They go their way, and you go yours, and you seldom stop to think about it.
But the Jewish people are the tenders of the garden. They are there, they are known, and they are deeply a part of it. But they do not look quite the same, act quite the same, talk quite the same. They there and yet they are apart, and the very joy that many of them have in that separateness can be baffling to others traveling through that garden.
If you have chosen a path of saying "how can I help?", meeting the gardeners and getting to know them better becomes a great joy to you also.
But if instead someone has chosen one of the many, many paths of searching for who is to blame?, then all to often they end up searching for someone enough like themselves to project all the evils they have perceived onto them, yet different enough that they never know them as personal friends or people with which they share a meal, a joke, a laugh.
And in choosing such a path, sadly, I think lies much of the reason for the deep and terrible evil -- it is just that, make no mistake and call it nothing less -- that has expressed itself with such particular persistence over the centuries in the treatment of Jewish people.