You’re correct, most people are misinformed about the Inquisition.
The Spanish Inquisition was instituted to weed out those baptized Jews and Moslems who pretended to be sincere Catholics, while they secretly adhered to the practices of Judaism and Mohammedanism, which is a most serious sacrilegious offense. They were also enemies of the State, which was Christian in principle and carried the Cross in battle against the Crescent. As further evidence, consider what Dr. Salo Wittmayer Baron, one of America’s foremost Jewish historians, has to say about this matter. I quote from “A Social and Religious History of the Jews” (N.Y., 1937, VOL 2 p. 58) -
“It appears to be a fact as well as a theory that Jews who never ceased professing Judaism were, on the whole, left undisturbed. - In the fourteen years of the activity of the Spanish Inquisition, from its establishment in 1478 to the expulsion of the Jews from Spain, we hear of only one persecution directed against a Jewish community, where the Jewry of Huesca was accused in 1489 of having admitted conversos (pseudo-converts from Judaism to Christianity) to the Jewish fold. It was precisely the inability of the inquisitorial courts to check Jewish influence on the conversos that served as a decisive argument for the Catholic monarchs in banishing Jews from Spain......
I’m a Protestant, but in light of the conflict with Muslim’s today, I think Belloc is looking like a prophet. The Catholic and patriotic Spanish historians didn’t have a chance when the Protestant and Jewish historians lined up the horrors of the Inquisition to beat the Catholic Church with, centuries after the Muslim threat had abated and people had forgot what the times were like for the Spanish immediately after the Reconquista was complete in 1492. Spain blazed as the world’s greatest power for a century and then drifted away and the power was in the hands of the Protestants. It makes for inaccurate or incomplete history when the historians have a grudge, as the Protestant and Jewish historians had against the Catholic Church and nations..