I'm not saying that the JWs loomed large in Hitler's consciousness; I'm sure he had much more important things to worry about.
The Witnesses did, however, stick out like a sore thumb, because they refused to salute Hitler or join the Nazi organizations. Any others who did so were obviously equally hated by Hitler.
So my point is, if the WT were to be correct about a worldwide totalitarian government arising under apocalyptic conditions, then the Witnesses would undoubtedly be a focus of hatred and persecution. Certainly not the only focus, by any means! But however 'pathetic' or 'retarded' we may consider them to be, they would still be considered a threat by a totalitarian government if they refused to submit to it.