Antisemitism as cartoon-ideology
Antisemitism is sort of an obscene graffito scrawled on the bathroom wall of bourgeois society. But it also has something of an air of mystical hocus-pocus and the direct, graphic power of occult symbols, like say, the swastika. Like cartoons, it is also plastic: shapeable and moldable to new conditions and subject to limitless morphological variation. Fans of other simplistic renderings of society will have a tendency gravitate to the world of antisemitic vignettes as providing more vivid and pornographic kicks.
There is a reason that almost every conspiracy theory tends to migrate back to antisemitism. It is, in many respects, the ur-conspiracy of Western modernity, always ready to assert (or reassert) itself under the right conditions.