That's an early middle ages translation of the word
keren. If you check the King James version, you'll note the correct translation. The nature of the mistranslation was known by Michaelangelo's time, as was the image of Jews with horns, the likely reason for the horns was artistic, related to the difficulty of portraying rays. For well over 500 years the correct translations have be known.
I can't speak for this particular incident, but the image has everything to do with the devil, and is commonly used even today. That you can't comprehend how a Jew would be offended by a characterization of Jews as devils is unfortunate.
You're putting words in my mouth. I'm NOT saying that I "can't comprehend how a Jew would be offended by a characterization of Jews as devils." I hope you don't think anyone around here is that stupid.
I'm saying that the "horned" headdress probably originated with the artistic convention that arose from the mistranslation from Exodus . . . NOT from a desire to portray Jews as devils. In other words, it had an innocent origin, no matter how offensive it may seem in retrospect.
Consider also that this type of headdress was pretty well known in medieval and Renaissance fashion - again having not a thing to do with devils.
