... XML is case-sensitive, so yes, SceneGraph XML is also case-sensitive, at least with respect to the element names.. I don't think attributes are case-sensitive, though.
Hmmm. XML being case-preserving does not create semantical "mandate" for roSG that uses it to be case-sensitive. Two illustrations:
(a) roXmlElement is not case-sensitive (unless you want it to)
(b) your observation that roSG currently is case-sensitive for elements but case-insensitive for attributes shows it can do whatever the heck it wants (XML is innocent)
So seems it's been the road of least resistance for roSG on this so far, not a matter of principle.
This diversion aside, whoever knows something on OP's question, should answer.