Help wanted
datavisualization also does provide compatibility with LaTeX as mentioned in the manual. But here, \rm, \bf, ... are deprecated in Latex2e so I don't think "wont-fix" is the correct way to go with this. Why not some branch having \rm when using Plain Tex and \rmfamily when using LaTeX (or the other supported TeX-variants).
datavisualization also does provide compatibility with LaTeX as mentioned in the manual. But here, \rm, \bf, ... are deprecated in Latex2e so I don't think "wont-fix" is the correct way to go with this. Why not some branch having \rm' when using Plain Tex and\rmfamily' when using LaTeX (or the other supported TeX-variants).
.... i.e. \mathrm should actually be used...
change \rm to \rmfamily