We see the current deadly mass shooting on Bondi Beach in Sydney Australia. What motivated such hatred, how could they kill so many innocent people? What we see, is basically a attack much like the Pogroms of old, to wipe out the Jews.

Antisemitism in the form of persecution and Pogroms were happening way before the Holocaust, and everyone knows what happened in 1492 in Spain, but something else happened that year. In 1492, King Ferdinand II of Aragon and Queen Isabella I of Castille issue the Alhambra Decree, mandating that all Jews be expelled from the country. History records what happened, "Spanish Jews were forced to renounce their faith or leave their thousand-year homeland behind. Meanwhile, the Spanish economy crumbled as hundreds of thousands prepared for departure, liquidating their assets and scrambling to arrange their affairs."

This had started even earlier back a century before, in 1391, when a wave of anti-Jewish riots swept through Spain, where thousands were killed. Others were forced to accept Christianity, so you can see the problem with the sincerity of these "conversions", so many of these "converts" now became persecuted by the Inquisition. And everyone knows the Roman persecution of the Jews leading up to the destruction of Jerusalem in AD 70, and millions being killed or were exiled or fled for their lives.

So why was there such hatred of the Jews, it cant be explained by the accusation that the Jews were Christ-killers., as anti-Jewish riots swept through Roman Empire as Christians were dying in the Coliseum and spread even in non-Christian areas. So what made them different than the people in the other nations and areas, well the day of worship certainly made them stand out and distinct to say the least.

The descendents of Jacob (renamed Israel) were chosen by God to be His special representatives (His people) preserving and spreading the important truth; the LORD was the One and only true God.
For thousands of years they held fast to this distinction -- the chosen people part at least, though they wandered away from their commitment to God many times.

During the time of Christ's first advent, and for a few years after, the Jewish people held themselves quite aloof from "those Gentiles". There was definitely a superiority complex. It made Paul's ministry to the Gentiles, challenging.

The Jews as a nation were very much against becoming subservient to any nation who sought to subjugate them. Rebelling. Both times that Jerusalem fell and suffered destruction (to Babylon first and later to Rome) was because they continually rebelled against the system in charge. That legacy or reputation, sadly, has followed them, even when they live as upright and supportive citizens in society.

One of the biggest reasons Jews are distrusted, is because they are smart, shrewd, business men. Not all of them of course, by far the larger part are simple people facing common challenges, but enough of them are in control of a lot of money and assets to make other people worried.
Example: The Rothschild family is arguably the most famous European banking dynasty in modern history. But their fame has also ignited and fuels the anti Jewish sentiment as well, https://www.britannica.com/topic/Judaism
Then there are several men back in 1903 who wrote a whole "secret plan" that the Jews are alleged to be following in their attempt to control the world. Called, The Protocols of the Elders of Zion. Those protocols are still around somewhere, those who believe it's true see the Jews as threat.

The Bible, of course is clear -- Jews and Gentile are made one at the cross. All have sinned, neither have any entitlement to heaven over the others based on ethnicity or human heritage. All need Jesus Who is offering salvation to all who will come to Him.
Christ died for all, each person is very important and beloved to our Savior, no matter what their ethnicity or heritage. The path to eternity is open to Jews and Gentiles alike -- "by the name of Jesus Christ of Nazareth",
"Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved. (Acts 4:10,12)