Hard to imagine "the blame" being put on any one person. It was a really sad, horrifying tragedy that unfortunately happened. Fair officials should of been monitoring the radar and been far better prepared. Even if they didn't know they strong winds were coming, they knew a heavy downpour and dangerous lightning was on the way an hour or two before the storm arrived.
This youtube video below shows the radar that evening. For nobody to realize bad weather is on the way is almost incredible to me.
http://www.youtube.com/watch?v=lIwttmaaUwE
No way one of the radio personalities on site should be blamed for this. At the end of the day, it is a Indiana State Fairgrounds show. And absolutely ANYONE could have grabbed a mic on stage and told people to seek shelter. Did not have to be a guy from a radio station.