I think the eccentricities and the “growling” were a distraction for viewers and failed to bring Casey the support he needed to go further in the competition. I cannot say I am surprised by this as Casey is not mainstream enough to be the next American Idol.
Song choice is always important. Casey tended to pick obscure songs that viewers could not relate to. Of all the material from Carol King week to choose from; case in point.
Farewell Casey. You are a talented musician and hopefully will find your niche in jazz.