Jonah Goldberg is a modern writer who tried to turn the reductio ad Hitler argument on its usual slingers ("Liberal Fascism" is the book, I assumed everyone knows this etc). While he is nuanced about it, those who caught up the idea are not, and have become as silly as those he was wittily denouncing.
I apologize for hurrying through your sentence structure. But you still used the “fruitcake” label, after castigating others for calling Horowitz derogatory names. How does that add up?