I was reading that antisemitism dates back to Greco-Roman times. I read that the resentment stems from he reaction to Jews' insistence in remaining apart and together.
Yes, sadly. Christianity was born in the cradle of Jewish oppression by the Roman Empire.
From what I have read, the conspiracy theories we see today - this belief that there is a global cabal (yes I’m aware of the roots of that word) of powerful Jews running everything behind the scenes - has roots that go back to the Middle Ages. At that time Jewish people tended to be more educated and sophisticated than their Christian neighbors. They also were the moneylenders, because the Christian Church at that time taught that Christians were not allowed to lend money or charge interest (known as usury - we use that term now to mean predatory or unreasonable interest but back then it meant any interest). But moneylending is essential to support a business and trade class, so you had banks emerging run by Jewish people who, as you pointed out, also tended to live apart and maintain their own traditions. You can draw a direct line from here to the antisemitic Shakespeare character of Shylock and down to the hateful cartoons and caricatures being shared on social media today.
You also had the church directly teaching terrible things about the Jewish people in the Middle Ages. Unfortunately that hasn’t entirely stopped in some corners even now, though it’s not as blatant. I remember hearing in church as a child that the Jewish people could not be saved, because they had the first chance to come to Christ when he was here, and those who are still Jewish today are descendants of the people who rejected that chance. This was conveyed with an air of profound sadness rather than hatred, but wow, what a message. I’ve also heard echos in some evangelical circles of blaming the Jewish people for the killing of Christ (without seemingly much understanding that Jesus himself was Jewish). (Other evangelicals seem to have more understanding of their Jewish roots and reverence for the Jewish people as the first chosen ones of God. It’s a complicated relationship between Christianity and Judaism here, I think.)
This was among many reasons I rejected the church of my childhood. It didn’t make logical or moral sense to me even then. But I saw adults around me accept this reasoning without any critical thought, just a knowing nod.
Sadly, these historical echoes are still driving antisemitic hatred today.
In the USA I think we are afraid to speak up about anti-Semitism. I think we feel that if we do not name it, it will not exist and will not hurt us
I think there is a lot to this. I also think we have so MANY problems right now with hate crimes of all kinds. Anti-Muslim sentiment. Racism against black people especially, but also Hispanics and other non-white people. I think many of us feel so overwhelmed by all of it it’s getting hard to name and point to the roots of each individual incident. As you point out, this was not even our only hate crime this week. There have been so many over the past year it’s hard to react to each one. But we can’t let ourselves become numb. We have to remember to keep calling out and naming the evils. We have to shine a light on them, because they thrive in the darkness.