Some people seem to use 'processor' to mean an XML parser.
I do not think that the latter people have a basis in the XML standard. Maybe I'm just extrapolating incorrectly from SP's design and my design of my own systems. My PyGrove uses the same system. The only way I could imagine a parser being unfit to create a grove is if it did not output enough information for the grovebuilder to do so. This statement makes more sense to me than your previous one.