They are framing it about child labor because a child died.
Who/What agency is investigating the death is not relevant to the fact that a child died while working in an industrial setting.
They are framing it the way they are because they do not think that children, or teens, should be legally able to work in these kinds of settings.
This isn't a "fine" to Amazon. 25 million dollars is just the cost of business.
Make this 250 or 500 million and then... Maybe.... it's a fine.