Given the 12039900398 chances Sinclair received in his career, i feel Guppy deserves a crack.
Here's Latham's last test innings too:
Because Sinclair got more chances doesn't mean Guptill automatically should as well. He's proven that he's not a competent test opener. I'm not a massive fan of either Fulton or Rutherford but that form is just atrocious, he needs to get some Plunket Shield runs under his belt before I'd consider him for selection - something Latham has done of late.
EDIT: On second look, he has notched some PS runs recently, but most of them came on the absolute largest road of all time (Ask Topleft about that one). I maintain I'd rather have somebody new - Guptill's ODI form has also been fairly average and that's where he's much more suited, so hardly a promising sign.