You are contradicting yourself. On one hand, you speak of class as "a very complex thing, a composite of an enormous number of other mediations"; at the same time, you establish a chain of equivalences among any number of oppressions in such a way that one word -- racism -- will do whether the question at hand is white supremacy in America, oppression of Koreans in Japan, anti-Semitism in Germany, or whatnot -- all various manifestations of the same Essence in your opinion.
It appears to me that the "complex" part of "a very complex thing" has gone out of the window! This even aside from the infelicitous description of class as "thing."
Now, racism & anti-Semitism & oppression of Koreans in Japan. Modern anti-Semitism, unlike racism & oppression of Koreans in Japan, has portrayed the Jews as the emblems of "finance capital," omnipotent & cosmopolitan, and at the same time as the harbingers of "Bolshevism" (though the latter stereotype has by now become obsolete with the death of the Soviet Union). Unlike blacks who get labeled "underclass," the Jews tend to be thought of as the "overclass" and/or "overeducated," so to speak.
The post-WW2 oppression of Koreans in Japan (unlike American racism & German anti-Semitism) has resulted in the treatment of Koreans as perpetual "residents" -- Zainichi -- rather than as subordinate members of the Japanese empire to be assimilated through colonial impositions such as soshi-kaimei or American ideology of the "melting pot":
***** Negation of both rights as Japanese citizens and as foreigners
How did the Japanese government treat Koreans compelled to remain in Japan after WWII? They treated Korean residents in as absurd a way as with their previous colonial policy [Mintohren 1989]. The post-war Japanese government negated both Korean rights as Japanese citizens and as foreigners.
For example, Korean schools were established in many places in Japan after the end of WWII. They were built by Korean parents who wanted their children to learn Korean language, history and culture in preparation for their future return to Korea. However, Japanese authorities suppressed these Korean schools, stating that it was not appropriate that Korean children were educated as foreigners since they were Japanese citizens.2
On the other hand, the Japanese government stripped Koreans residing in Japan of their right to vote in December 1945. In 1947, Koreans residing in Japan became subject to the Alien Registration Ordinance. The grounds for this treatment were that Koreans who did not have their "koseki" (family registration) in Japan were not seen as "true" Japanese, even though they were Japanese nationals. Even after the San Francisco Peace Treaty was effectuated in 1952, the Japanese government still treated unrepatriated Koreans outrageously. When the treaty came into effect on April 28, 1952, the Japanese government unilaterally stripped Korean residents of their Japanese nationality. They did not even give Korean residents a choice between a Japanese, or a Korean nationality.
Moreover, as it obtained independence from the Allied Nations' control, the Japanese government awarded compensation to war veterans and the families of those who died. However, it was not awarded to those Korean veterans who were forced to become Japanese soldiers during WWII, nor to their families. This was on the grounds that they were not Japanese nationals when the laws were established, even though they had been Japanese nationals during wartime.
In addition, Koreans conscripted into the Japanese army were given orders to abuse captives of the Allied Forces by their superiors. These Koreans were penalized and executed as war criminals even after they had their Japanese nationality stripped. The Japanese government and the Japanese Supreme Court rejected Korean protests relating to this unfair treatment, stating that despite the fact that they were no longer Japanese nationals, those Koreans forced to commit war crimes would be found guilty as "Japanese nationals", and there would be no exemption from punishment [Utsumi 1982].
<http://www.han.org/a/fukuoka96a.html> *****
The end of colonialism & the beginning of the Cold War changed Japan's treatment of Koreans -- from second-class imperial subjects to "residents" who are neither quite Japanese nor quite foreign. Koreans lost the right to vote under the American occupation & then citizenship with the San Francisco Peace Treaty.
During the first several decades of postwar history, Koreans in Japan were ideologically split sharply, with the majority favoring North Korea & a large number actually relocating to North Korea (nearly 2,000 Japanese women married to North Korean men went to live in North Korea also); now the ratio has reversed, and it is said that two thirds of zainichi favor South Korea, estimated on the basis of memberships in the capitalist South-oriented organization Mindan (the Zainichi Koreans Union in Japan) and the communist North-oriented Chongryun (the General Association of Zainichi Koreans in Japan).
It goes without saying that this type of clear ideological division does not exist among American blacks!
If you insist on analogy, I might suggest that the below reminds me of what the English did to the Irish.
***** [I]t was primarily Japan's colonization of Korea that influenced a large number of Koreans to migrate to Japan. After the annexation of Korea in 1910, Koreans were forced to become the subjects of Imperial Japan. The occupying colonial policy imposed severe control on Korea. The Japanese government confiscated a significant amount of land from Korean landowners from 1910 to 1918.
From 1920 to 1934, Japanese authorities initiated a project to increase rice production in Korea, and exported the major part of the rice to Japan causing serious famine among Koreans. <http://www.han.org/a/fukuoka96a.html> *****
Being black in America, unlike being Jewish in Germany & being Korean in Japan, has to this day been conflated with being poor, employed or unemployed (hence few ever speak of "black trash" -- for black itself signifies poor here, so it's redundant to say "black trash" -- whereas the white poor get a special label "white trash" to preserve the ideological equation of "white" & "middle class").
Jews in Germany, Koreans in Japan, & blacks in America do not occupy the same material & ideological locations in each nation's class & ideological formations.
Yoshie