Biden has been an Israel beneficiary for longer than most of us has been alive.
And a lot of people don't quite understand what Israel means to a liberal anti Semite. What Israel represents is the answer to what they called the Jewish question. A genocide was off the table as a result of Hitler so how else could they keep jews out of their neighborhoods and businesses? Anti Semitic conspiracies were mainstream at the time and people really DID believe(despite attempts at rewriting history so it was only the Germans that were antisemitic) that if you allowed jews into your country they'd inevitably entrench themselves and take the reigns of power to manipulate people into doing their bidding. America and Canada and other countries in Europe treated Jewish people who tried to flee Germany early on like pests and even tried to send them back. How do you answer the Jewish question when force is off the table and you had declared war on Germany, the country who wanted to eliminate them?
They used the tool they'd been using all along: colonialism.
The answer was simple: give up a piece of colonial land, tell Jewish people that they belong there. Pump billions in making sure the standard of living there can compare to the European countries they called home for generations and then finally convince them that true jews belong there and that anyone who criticizes that government hates jews.
They literally used the collective trauma they caused the jews after centuries of discrimination exploding into a bomb of industrialized murder and violence with the holocaust, as a weapon to force them into supporting Israel. Then the idea is that the unwanted ethnic group could go there and stay there. Out of sight, out of mind. You get to be as antisemitic as you want so long as you're propping up Israel. Every now and again the mask slips, like when Trump said "your prime minister Netanyahu" when he was speaking stateside to a gathering of Jewish people. Thereby telling these citizens that they're not real Americans and should be in Israel actually.
By fusing the manufactured state they created as a dumping ground for an ethnic group they considered undesirable with that ethnic group's identity, you get to equate any criticism with that government with criticism of all jews as an ethnic group. It is a strategy that has been as evil as it has been genius. The best part: because that country is loyal to the people that made it, they will carry out a campaign of colonialism and secure resources by destroying their neighbors and occupying them. So then the real estate, energy, and other big companies based in Europe and America get to reap the benefits of colonialism without being DIRECTLY linked to it.
