In 2017, he transferred 78% of his net worth ($18 billion) to his grantmaking organization, Open Society Foundations. Because of his history in the Holocaust, Soros and his groups have donated hundreds of millions to left-leaning candidates and organizations that fight hate, injustice, and authoritarianism.
He’s often cited as the mastermind behind the ‘great replacement’ – the conspiracy theory that Jews are importing nonwhite immigrants into America to weaken the political power of white Christian men. Of course, non-Jewish billionaires also give millions to American politics, but they rarely get the same ‘boogeyman’ treatment. Also, "Billionaire Boogeyman" is a pretty good name for a rap artist, if anyone wants it.
The Rothschilds, a wealthy European Jewish family, has also been the subject of world control conspiracy theories since the early 1800s.
So when you hear people say “Soros-controlled” or “Soros-backed,” they aren’t just identifying a political donor – they’re often implying that Soros is one of the wealthy Jews trying to control the world and eradicate white people.
TL;DR: Criticizing rich people’s political influence is not antisemitic, but in the case of George Soros it quickly moves beyond reasonable critique and into antisemitic conspiracy theory.
Not-Fun Fact: The ‘puppet master’ label was also wielded by the Nazis to turn Germans and other Europeans against their fellow Jewish citizens. Not to be confused with Master of Puppets, the third studio album by Metallica, released in March of 1986.