I remember reading an article on Judge Jeffreys and the Bloody Assizes and how it had left such an impression on the West Country mind for centuries. The argument was that it wasn’t that the Assizes had killed all that many people but, rather, the sheer ‘performance’ around every execution so that the whole business went on, and on, and on.
I think there’s a lot of that when talking about things like the Inquisition - it didn’t take huge numbers of ‘performances’ to terrorize a population.
On the other hand, while the numbers involved may be exaggerated (but what did happen to all those Cathars?), “wasn’t us Guv, it was the State,” given the interrelationship between Church and State, isn’t all that convincing.