There is a popular fiddle tune called "Devil's Dream." I was always given to understand that the name derives from the fiddle itself which was known as the Devil's rocking horse or the Devil's riding horse. Fiddle music was thought to be evil because it caused people to dance and throw off their inhibitions. The sensuality of rhythmic music has been understood from ancient times and in some overly anile cultures where sensuality was condemned, any music that seemed to encourage sensuality was thought to be evil. It turned the minds of the faithful away from spiritual contemplation and towards the purly physical.
"Of course that's just my opinion... I could be wrong."