Yes, there was quite the discussion about this on the Nevada Shooters site, and everyone universally agrees with you, including the dealers. There is already a very well-supported bill in front of the legislature right now to make it absolutely clear that firearms meet the existing exemptions in state laws for occasional interstate purchases/transfers. It should go into effect in July, if I remember correctly. Someone at the tax department did this on their own, and are wrongly citing existing laws, but they apparently have the authority to enforce it until they are officially overridden. The governor's office has been silent.