They don't either understand that not all Jews are George Soros. They don't understand that not all Jews push an intersectional, interracial agenda or force people to accept that males and females are interchangeable. They don't understand that not all Jews are Karl Marx or Leon Trotsky. In fact, those so called "Jews" are not religious at all and don't care about Judaism in the least. Yet the meme propaganda that White Supremacist Nazis post are always of Jews with a beard, yarmulke and payos -- the Jews that are actually Right wing and Conservative.
These people hate Jews far more than they hate Muslims. They are angry and writing how this was all in vain because "he didn't mention the Jew" in his manifesto and that he didn't kill even one Jew.
I think about this a lot, even more now that there seems to be anti-semitic acts cropping up in the news daily. I work in a firm where, quite literally, I am one of two shomer shabbos people in the firm, and the only one to wear a yarmulka. There are many other jews in the firm, but very few of them have any kind of 'shaychus'.
I realized, that for most of these people, I am the ONLY Orthodox person they know, and possibly have ever known. I am the source of all of their questions about Judaism and the mideast. I get asked questions (thankfully know one at work has asked me the 'sheet' question) ranging from - "Why is Israel killing Palestinian Babies'? to 'My daughter is going to a friend's bat mitzvah next week, how should she dress for synagogue?".
In a sense, I am the ambassador for the jewish people, and I do my best to be a good ambassador.
IMHO, most hatred comes from ignorance. If you do your best to educate the haters, some of them might just become non-haters.