Rolling the ball to 1st base 7-8 coach pitch?

This is minor coach pitch softball 7-8yr olds, we played a team and they had thier pitcher and second basemen roll the ball to 1st to get the outs. Is this a legal defensive play, the umps called it an out every time, but questioned it and lost. I feel they need to make an effort to get it there, not just catch it and throw it down and let it roll. There is nothing in the rule book about this, but I don't agree with the call.