in japanese its said "suna no shinobi", and in english its said "ninjas of the sand". The same way gaaras name is "sabaku no gaara", but in english it wouldnt make any sense saying "desert gaara", so we say "gaara of the desert". You could still keep the first phrase in tact by saying "sand ninjas" but that doesn't sound as good as "ninjas of the sand". Understand?
Err, that isn't what I asked for. I already said I know why it works backwards. All I'm wondering is when Kankuro said "Soona" the translation should've been sand but it was ninja.
Is it just me that doesn't understand this? Eh "shrug" ok w/e.