Perhaps we can take a recent article in Historical Materialism by Prof. Landa ('Rootism, Modernity, and the Jew') just as a starting point for debate on race etc. Some quotes:

"To the extent that the Enlightenment embraced anti-Jewish attitudes, Judaism was seen as a stubborn, atavistic relic, resisting the claims of the new times. This was integral to a general critique of traditional religions, reflecting deistic (and sometimes covertly atheistic) positions. ...

If the Enlightenment chastised Judaism mainly on account of an attributed backwardness, the Romantics feared its progressive thrust. ...

Qua wandering or eternal, the Jews were seen as embodying the spirit of restlessness and lack of roots, undermining tradition and fixed national and racial identities; their dynamic role as revolutionaries, conspirators and rabble rousers was ritually denounced."

In this figure of the Wandering Jew however, I would also draw attention to the "eternal" aspect (and not only the rootless wandering aspect like professor Landa here does), as in the condition of an incapacity of dying. You might wonder, isn't eternal life a blessing rather than a curse? Well I suspect the old age implies something negative. The image of the wandering Jew is I think usually an old guy with a white beard in a kaftan, not a young energetic fighter on the barricade.

This idea that for reactionaries "modernity" = Jewish, is maybe for today's progressive Jews (or philo-semites) in some ironic way, "cool" to endorse or for progressive academics it sounds appealing. But consider for a moment, that the opposite might at least be true as well. My notion that reactionaries deem "antiquity" (for lack of a good term) as = Jewish, would explain their Jew-hatred then, for example, as follows: their resentment stems from the fact that the Jews have an older and thus more based claim to tradition and nationhood. The progressive theorists of antisemitism almost can't even consider this, because they are unwilling to see Jews as a nation (merely a religion, or socially-constructed, imaginary community etc.). In a struggle between races (such as held in the reactionary worldview), having a greater antiquity arouses resentment.

I read in some random German text from the 1930s a naive point made in passing against the Nazis: the (I think Jewish) writer mentioned that archeological evidence indicated that Jews were present in Germany in Roman times, before the German tribes had migrated there (and so in a way, are more "rooted" in Germany than the Germans themselves). I imagine this argument would only fuel Nazi antisemitism even more, because it reinforces that antiquity = Jewish. Maybe the Nazis' endorsement of an Aryan race can even be understood as an attempt to establish an older origin for their nation. Aryans being older than the Germans, thus providing a stronger basis to rival Jews as a legitimate/self-confident race (as Aryan).

The rootlessness of Jews would be seen as a sign of their primitiveness (and not = their modernity), namely as remainig at the level of desert nomads, as incapbale failures at building their own civilized normal nation. The Jews are Wandering, because they are punished and cursed, because they failed as a nation, bound to remain so eternally.

So when the progressive theorist of antisemitism almost joyfully notices, that the reactionaries hate Jews for their statelessness, they ignore (or wish to disagree with) the point that at a certain stage in history (in antiquity) the emergence of "rooted" states was progressive (even for Marxists), as compared to more primitive forms of social organisation (such as tribalism, regionalist clanism).