I think it's a marketing thing in two parts 1) protecting their breeding lines (annoying!) and 2) people are generally scared of "Latin Names" - even sticking "Phalaenopsis" on there is a jump (rather than just Orchid or Moth Orchid). Imagine a label for an unregistered hybrid of unregistered hybrids...! That would really put people off.
Of course, the ideal would be a balance, a generic, attractive colour phalaenopsis tag for the noobs, along with a "boring" accurate tag or label in or on the pot.
I suspect many people buy in compots/flasks/seedlings/NBS and grow them on just for the retail market, who on the whole don't care - it's "just a pretty plant for my windowsill"; indeed many of them will be tossed when the flowers fade (gasp) (shock) (horror).
I'm sure the plant geeks of any group of plants get similarly irked by retail non-labelling - I can imagine the African Violet people getting really annoyed with pots saying "African Violet".
What's really hilarious is reading someone's book about orchids decrying poorly labelled retail plants, and then finding poorly labelled retail plants in their orchid selling greenhouse.