What I don't get is, some people say that madara gave Nagato the rinnegan, almost like he confirmed it. Plus they say you don't need senju blood to unlock rinnegan, like he confirmed it. What we do know is tobi told konan he gave nagato the rinnegan, but we know that's a lie and kabuto said that rinnegan is the evolution of sharingan, but we never got a confirmation that you don't need senju blood to activate rinnegan. Well we know that madara got senju dna after the fight with hashirama and he activated the rinnegan before he died wich was long after the fight. But some people keep saying it's a natural evolution of the sharingan...
Now we don't know much about the uzumaki clan, besides being distant relatives of senju and all we can do is speculate. So saying that uzumaki can't activate rinnegan can't be confirmed. We haven't been givin much information about the uzumaki clan, a clan wich our main character belongs to. Think about it, Kishi must be holding information back for some reason. But we know about the rinnegan, an ocular power that makes it's appearance when the world is in choas, wich means, you've got to experience some kind of trauma to activate it and we know Nagato experience pain when he's parents got killed, plus it was during war. So saying nagato couldn't of activated the rinnegan, is not a fact.