Again, I am just waiting for Mandel to attack Vance for having a brown wife.
High-risk, low reward.
First, consider that a lot of the groyper types are more ambivalent about this kind of interracial marriage than any other. The thought process goes: Asian woman -> closer to "trad" culture -> less feminism.
Secondly, if hardcore mudslinging like that doesn't backfire, it proves all kinds of dogwhistles can work. Then Vance can just respond with blatant antisemitism, which probably has more staying power.