Well I don't know what you can call a religion that encourages cutting off the heads of those who refuse to convert

I'm no apologist for any religion, as is possibly known hereabouts, but I know of no religion that encourages cutting off the heads of those who refuse to convert. What I do know is that a few nutters professing to belong to certain religions might have such predilections. Similarly, the Catholic church does not encourage child molestation and institutional abuse, though a few nutters professing to be members of said church might like to either practise or cover up such abuse. Why, one such fellow of the latter tendency has just been made a saint!

I'm no apologist for cheap Chinese harps either, though, like with a lot of kids who went on to play proper ones later on, they sort of got me going.