It’s utterly specious. To find it credible, you would have to believe that Jo Rowling, despite being very publicly on record as defending and standing up for Jewish members of the Labour Party in the face of the vicious anti semitism they were being subjected to within the party, is actually, secretly an anti semite, and she coded this into her books.
Then you’d have to believe that in spite of the whole series being rife with allegories of fascist societies, how they come into being and function, how they can be defeated with bravery and honesty, she actually secretly believes the exact opposite, and shares the anti Semitic sentiment that underpins modern European fascism.
You’d further have to believe that the correct way to address this is to give her a thorough public drubbing for it, question her character and morals, set hordes of Internet bullies on her, rather than, you know, discussing where the folk tales about goblins come from, what she drew on, to what extent they themselves had anti Semitic tropes baked into them etc.
You would, in short have to be an authoritarian bully, and a none too bright one at that.