It's a legitimate question. What exactly makes a US passport more expensive? The cost of labor, shipping, and manufacture isn't 4.5x here than that of Ireland. Even If the a US passport is less than a cup of coffee a month, that doesn't make the cost justified.
Other countries see passports as a normal thing to have - a second identity document to keep at home in case your wallet is stolen, etc, and so charge a reasonable price for it.
I think the US government might see it as a thing that wealthier people use for travel abroad, and so feel justified in charging more for it.
This is a children's passport; an adult Irish passport is basically the same price as an adult US passport. Given my experience growing up in Ireland, I would guess that the Irish government is subsidizing passports for children.
