Charging anyone in this case benefits no one but the government. Whether it be fines or imprisonment of hte babysitter, or parents, it would only serve to ruin people's lives. The parents are presumably productive working people trying to raise their kids. Charging them would break up the family, present a financial hardship, possibly result in loss of their income, and they would end up with a broken up family and on welfare. This benefits no one except the government.
If the babysitter was charged it would result in a later graduation from high school, ridicule from peers, a great expense for her and possibly her family, and in general hurt her learning and earning potential for years (decades?) to come. This would benefit no one except the government.
it's absurd to charge a 5 year old. She likely didn't fully understand what she was doing or what the end result would be. Give it a few years and it will sink in hard. It will be a guilt she will live with for the rest of her life.
If there was no malicious intent then there is no reason to send anyone to prison, and there certainly isn't any reason why government should profit from this. Sometimes bad things happen and that's the way it is. All involved walk away with some loss and some learning from it.