Actually, I'd suspect there are a good number of Protestants themselves who don't know this. They grew up with a certain "black legend" of the Eeeevil Catholic Church, and finding out that Protestants and Anglicans were out there torturing and killing is often a real surprise to them. Most of them are also stunned to hear that Henry VIII (who appears to be a hero in the Protestant mind) and his immediate successors, in addition to killing Catholics who refused to accept him, destroyed ancient churches and monasteries and carried off or destroyed much of the England's patrimony of medieval religious art. I don't think there's any point in dwelling on these past horrors, but at the same time, I don't think it's fair that Catholics are tarred with this brush while Protestants get a pass on their equally or even more violent attacks.
Well it is something that I want to learn more about.I really should set apart time to do more research on this part in history.