imo (and I’m certainly no expert) in very simple terms, at least from a European perspective it is because Jewish people were far more widely dispersed and independently successful from medieval through to industrial times throughout most of Europe than any other ‘non-indigenous’ racial group. Combine that with (unlike medieval Christianity) no cultural restriction from lending money and an ability to blame Jewish people for the death of Jesus (which is absurd on so many different levels) then you have a cocktail for suspicion, blame and recrimination which took root and endured.
In even simpler terms, it is because they refused to be cowed and subservient that they were historically persecuted - and that gives rise to enduring suspicion and resentment today in some (paranoid and malign) quarters, with some people genuinely believing they run the world.
Jewish people have arguably the most fascinating and admirable history and culture of any people on the planet and it’s perfectly understandable and laudable (and correct) why they were given a homeland after WW2. It was Europe’s attempt at an apology for the appalling way they had been treated for many centuries culminating in the Holocaust.
Like so many times when people are trying to right a wrong and when lines are redrawn on a map, however, it wasn’t fully thought through. I think the last part is hard to argue against, given the current state of play.