I think you mean S. rosea :P S. rubra si so deffinitly a different species that no one ever thought it was in the purpurea group
The reason those people are so ready to grasp molecular studies for VFTs/Aldrovanda/Drosera is because we are mostly dealing with "groupers". They like to group things together. So of course any molecular data that makes a group is wanted while data the splits up a group is ignored.
IMO (not that you asked) I don't think S. rosea deserves full on species status but I would happily accept it as S. purpurea ssp. rosea.