While many voters embrace Kamala Harris’ candidacy and the fact that she is a multiracial woman without any biological children, some Republicans are using her identity as fodder for attacks.
The people viewing it as a weakness were going to attack her no matter what, whether she was just black, just Indian, or just a woman. Adding the extra labels doesn't really amplify their thinly veiled bigotry, she's going to lose negligible support for being biracial than if she was one or the other, and will possibly appeal to a broader cross section of apathetic voters.