alt Hacker NewsXML was designed as a document format, not a data structure serialization format. You're supposed to parse it into a DOM or similar format, not a bunch of strongly-typed objects. You definitely need some extra tooling if you're trying to do the latter, and yes, that's one of XSD's purposes.
that's underselling xml. xml is explicitly meant for data serialization and exchange, xsd reflects that, and it's the reason for jaxb Java xml binding tooling.
get me right: Json is superior in many aspects, xml is utterly overengineered.
but xml absolutely was _meant_ for data exchange, machine to machine.