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?