GenZedong

I'm not discouraging anyone to read it, but do it with a more critical eye. The way people get emotional when someone criticizes the work Settlers should be an indicative that a critical discussion over it is seriously lacking.

There are many excerpts from the book that are actually very informative and useful, the author surely spent many years researching for this work. But the general thesis of the book is that white workers are inherently reactionary and counter-revolutionary, and they always act under the premise of being white, always protecting their white privilege. The main argument of the book is that white workers are just as much enemies as the bourgeoisie itself. J. Sakai does not present a coherent understanding of labor aristocracy, and he treats all white workers as if they were all labor aristocrats.

In contrast, the Marxist(-Leninist) attitude towards race was to first consider class relations, and work to overcome racism through class solidarity. This was exactly what the Chinese communists under the leadership of Mao Zedong did in China. In China, from Mao's time until today, there has been a Han ethnical majority. This was Mao's attitude to Han chauvinism:

The minority nationalities in our country number more than thirty million. Although they constitute only 6 per cent of the total population, they inhabit extensive regions which comprise 50 to 60 per cent of China's total area. It is thus imperative to foster good relation between the Han people and the minority nationalities. The key to this question lies in overcoming Han chauvinism.
On the Correct Handling of Contradictions Among the People

In some places the relations between nationalities are far from normal. For Communists this is an intolerable situation. We must go to the root and criticize the Han chauvinist ideas which exist to a serious degree among many Party members and cadres, namely, the reactionary ideas of the landlord class and the bourgeoisie, or the ideas characteristic of the Kuomintang, which are manifested in the relations between nationalities.
[...]
In other words, bourgeois ideas dominate the minds of those comrades and people who have had no Marxist education and have not grasped the nationality policy of the Central Committee. Therefore, education must be assiduously carried out so that this problem can be solved step by step. Moreover, the newspapers should publish more articles based on specific facts to criticize Han chauvinism openly and educate the Party members and the people.
Criticize Han chauvinism

This is in line with Mao's understanding that Han chauvinism (or racism) was an ideological issue. In no way Mao portray Han people as inherently racist and incapable of overcoming racism. It follows Mao's teaching to "cure the sickness to save the patient":

In opposing subjectivism, sectarianism and stereotyped Party writing we must have in mind two purposes: first, "learn from past mistakes to avoid future ones", and second, "cure the sickness to save the patient". [...] But our aim in exposing errors and criticizing shortcomings, like that of a doctor curing a sickness, is solely to save the patient and not to doctor him to death. A person with appendicitis is saved when the surgeon removes his appendix. So long as a person who has made mistakes does not hide his sickness for fear of treatment or persist in his mistakes until he is beyond cure, so long as he honestly and sincerely wishes to be cured and to mend his ways, we should welcome him and cure his sickness so that he can become a good comrade.
Chapter 27 of Quotations of Mao Zedong

In Mao's China, the Han people was an ethnical majority. There was racism against ethnic minorities to the point even party cadres presented this reactionary tendency. One can argue that this may be only adequate to the conditions of China. But this attitude towards fighting racism by treating it as an ideological issue also was a part of the US revolutionary movements. Famously said Fred Hampton,

We don’t think you fight fire with fire best; we think you fight fire with water best. We’re going to fight racism not with racism, but we’re going to fight with solidarity. We say we’re not going to fight capitalism with black capitalism, but we’re going to fight it with socialism.

This was the reasoning behind the Rainbow Coalition, which united organizations representing several ethnic backgrounds, including Chinese, Latin American, white southerners, blacks, Native peoples, etc. This is what actually threatened the US establishment, racial solidarity towards a socialist struggle. J. Sakai's work just promotes race essentialism which actually preserves racism and bourgeois power.

Here is another good point-to-point critique of Settlers. And another. And yet another