Why are the Kasouras initially interested in spending time with Childan but then abruptly lose all interest?

Question

When Mrs. K. invites Mr. Childan for dinner on the phone in The Man in the High Castle he asks if it as friends and she ignores this question. Then when he comes they are interested in his perspectives on American literature. But after this they tend to snub him by, for example, coldly insisting he use the tradesmen's entrance. Is it because he wasn't familiar with the novel that Kasoura had been reading? Because he celebrated/praised the Holocaust of Semites at the Kasouras' dinner table? (Based on their dirty looks I half expected them to be revealed as crypto jews because they puzzlingly seemed to find the remark rather tasteless.)

Why did they invite him over in the first place and then, why did they abruptly change their feelings towards him so completely?

Answer 1

Childan seemed very interesting to them because of his knowledge of American history, and they invited him over to be able to gain a new perspective as somebody who was not Japanese and also extremely knowledgeable.

However, during the entire visit Childan basically only delivers canned responses and constantly just praises how the Japanese and German cultures are far superior, (him saying how boring Jazz music is, is a good example of this).

Throughout the entire dinner he basically is giving spoon fed responses in an attempt to impress his hosts, as opposed to being somebody that can think for himself at all, which is boring to the Kasoura's as he is just another person who has accepted himself as a subordinate to Japanese culture.