Hello everyone, I know I'm new here and this thread is old but I felt that I could shed some light on this issue. I'm currently on the last semester of my Ph.D. in Biology, specifically studying Cypripedium candidum ecology and evolution. I'm a little disheartened to see the apparent despise for taxonomists (I'm not one) and thought I might be able to offer some explanations that may make you all a little less irritated at the frequent name changes.
As you all know DNA analysis has revolutionized Biology and in particular systematics. What many of you may not know is that the field is anything but it stasis, it is constantly improving and getting cheaper. Where 10 years ago it may have cost thousands of dollar to sequence a relatively small number of species for a very small section of their DNA (700-800 basepairs) today a sequence like this will cost orders of magnitude less (at last pricing a single sample is $5-10). With this drastic decrease in sequence costs, researchers are able to sequence larger numbers of species and larger swaths of DNA in each of these species. When scientists talk about sequencing DNA, most of the time they aren't talking about sequencing the entire genome but simply sequencing small sections that are evolutionarily informative. Most often these sections are within the nuclear, mitochondrial, chloroplast or ribosomal genes. Each one of these sections evolve at different rates and are informative at different levels (i.e. between individuals, genus, species, sub family etc.). Due to the decreased cost and increased ability to sequence scientists are able to create much more accurate phylogenetic trees which inform us to the evolutionary history of the organism. By lumping things into a genus or species we are explicitly stating that at some point in the past, these species shared a common ancestor and have since evolved from that ancestor. I can assure you taxonomists are not just doing this to annoy you, each correction has an evolutionary reason.
In the case of the Neofinetia to Vanda issue, this change was announced in a peer reviewed publication this year in the Journal Phytotaxa by Dr. Lauren Gardiner in the article "New Combinations in the genus Vanda (Orchidaceae)". I have access to this journal and article so I can summarize it here. Based on new molecular evidence, species in the genera Ascocentrum, Ascocentropsis, Christensonia, Eparmatostigma, and Neofinetia are being reclassified to the genus Vanda. This reclassification as well as information on the analysis will be published in the forthcoming Genera orchidacearum. The Neofinetia treatment in particular was done based on molecular data, ease of hybridization and prior classification. Neofinetia falcata was at one point correctly classified as Vanda falcata in 1854.
Hopefully this all makes a little more sense and you all don't think us scientists are evil . If you have any more questions please feel free to ask and I will answer them to the best of my ability.