This law may not make sense. And it definitely will not prevent accidents like this in the future. But reactionary legislation generally stems from public pressure. When a tragedy like this occurs it is the human condition to want to blame and to demand immediate action that provides the perception of safety. I said perception, because we know this law doesn't actually provide safety. But before we blast legislators, we need to remember that the government generally acts at the people's bidding.
I will also offer this likely unpopular thought. While it is undeniable that the cause of the accident had NOTHING to do with human ride operation, you cannot ignore the fact that this ride operator was 24 inches away from preventing the accident from being as bad as it ended up being. It is unfortunate that this person didn't have the wherewithal to react in a crisis. Was that due to age? Maybe, maybe not. But I can at least follow the dotted line reasoning that has people looking to ride operation and considering changes.