One of the examples they give is very instructive:
Notre Dame Cathedral in the heart of Paris is among the most visited sites on the planet and a splendid example of Gothic architectureWikipedia adds:
Each year, millions flock to admire and photograph its flying buttresses and statuary, yet few take any real notice of two prominent female statues on either side of the main entrance. The one on the left is dressed in fine clothing and bathed in light, while the one on the right is disheveled, with a large snake draped over her eyes like a blindfold.
The statues, known as Ecclesia and Sinagoga, respectively, and generally found in juxtaposition, are a common motif in medieval art and represent the Christian theological concept known as supercessionism, whereby the Church is triumphant and the Synagogue defeated.
Sinagoga is depicted here with head bowed, broken staff, the tablets of the law slipping from her hand and a fallen crown at her feet. Ecclesia stands upright with crowned head and carries a chalice and a staff adorned with the cross.
The figures reflect the Christian belief, sometimes called Supersessionism, that Jesus was the Jewish Messiah, and that Judaism as a religion was therefore made unnecessary, by its own tenets, once Christianity was established, and that all Jews should convert. Today opposed by dual-covenant theology, this belief was universal in the medieval church. Synagoga's blindfold reflected the refusal of medieval Jews to "see" this point, which was regarded as stubborn.The point of Synagoga is not to assert the Church's superiority - its presence in cities with large Jewish populations prove that the intent is to prove Judaism's inferiority, to humiliate Jews.
The sculpted portal figures are generally found on the cathedrals of larger cities in northern Europe that had significant Jewish communities, especially in Germany, and apart from their theological significance, were certainly also intended to remind Jews of their place in a Christian society, by projecting "an ideal of Jewish submission within an ideally ordered Christian realm.
Humiliating others is certain indicator of low self-esteem.
Supersessionism holds that the continued existence of Jews is an anomaly. Jews were already second class citizens, but that wasn't enough. This artwork indicates not only that Jews should be subjugated, but that they are mentally ill for not embracing the obvious truth that their belief system has no legitimacy.
The very existence of vibrant Jewish communities in Christian Europe disproved the basis of supersessionism, and these elaborate sculptures and paintings and stained glass windows were meant to make Christians feel better by putting down Jews who somehow managed not to disappear as supersessionism would predict.
It is hardly surprising that the most antisemitic and anti-Zionist churches of today are the ones who still cling to supercessionism. Nor is it surprising that supersessionism is a keystone of the Palestinian Christian community, which embraced this philosophy in the Kairos document.
This attitude is more extreme than traditional dhimmitude. Muslims think that Jews have a place in society, but that society is run by Muslims and Jews must mind their second-class status. It isn't that they don't belong in society, they just have to know their place.
The proper analogy isn't between Christian xupersessionist theology and dhimmitude; it is between supersessionist attitudes towards Jews and Muslim attitudes towards Israel.
The existence of a Jewish state is the same challenge to the Muslim worldview that the existence of Jews is to Christian supersessionists. In both cases the very sight of the offending entity - Israel or Jews - is an intense source of shame, because it cuts to the heart of the belief systems. In both cases, they must be defeated in order to restore self-esteem and prove that their beliefs have validity.
One can say the same about how the existence of the Jewish people is a challenge to universalist ideology that cannot abide that different groups of people are really different, and no one symbolizes that better than the Jews.
Greater minds than mine have spent countless years pondering the nature of Jew-hatred. I think that the inability to reconcile one's own belief system with the very existence of Jews, or the existence of a Jewish nation, is a very good first step.to understanding the roots of antisemitism.