The Spanish Inquisition was the target of a propaganda campaign fueled by the novelty of the newly invented printing press. As a result, its place as the top symbol of all that was wrong with (fill in the blank yourself) is likely an error.
The above link mentions the YouTube video in the next link and seems to borrow quite a bit from it:
The video documentary is somewhat gruesome and lasts 46 minutes. It’s quite serious, but the first two minutes may seem otherwise, they seem to try to capture the vagaries of the myth of our imaginations.
The documentary fails to capture the entire importance of this myth today. It ends with references to the red scare of the fifties without getting into detail. Perhaps that’s because Democrats always controlled the House Un-American Activities Committee.
There is a more subtle aspect though. People with a vague sense of history may have the idea that the Spanish Inquisition was the inevitable outcome of some sort of religious tyranny that began with the so called “Dark Ages” and the Dark Ages were the result of the beginnings of Christianity since they coincided in time. These are false views. The film does dispel somewhat the religious tyranny angle as there is mention of the secular role. The dark ages were the result of the collapse of Rome and bad climate as far as I know.