Mauro, I really don't think you (or any of us) have to care about it. We can grow orchids without giving importance to what is on the labels (but of course we want a right ID). So, for me, if this is Colmanara or Odontocidium is a minor detail, i just like to know how the names are changing. In this case, it was a change from Miltonia warscewiczii to Oncidium fuscatum that originated the new name. In this particular case, I liked the change and in scientific terms it seems to make sense. in philogenetic studies this species does not belong to Miltonia and belongs to the anthrocene group (in Oncidium).
Actually, RHS has a particularly difficult job. I doubt they take it lightly, although sometimes it may appear so. It must be hard to decide what particular group of scientists are right and how the names will change. Taxonomic nomenclature will not stabilize, but indeed, nowadays it seems amost chaotic at certain times. Like the example that you give and with a lot of examples where Brazilian scientists are changing the names of the genera (like the great revision on Oncidium genus). To some it seems difficult to accept Brasilaelia, Brasilidium, Coppensia, Hoffmannseggella, Dungsia, Hadrolaelia and so on. Looking at these examples I really don't know how do they still care, sometimes it must be frustating.
What I do know is: my opinon is not relevant, scientists will continue to do science and they will change the names when they think it is needed (and sometimes when they need a new paper
). RHS will tend to follow them and so the names will always be changing. I would be happy if I could understand why and if the names are changed in a rate that shows good sense.