While that guy's thread is closed and I can't reply, I will state here some of the mos OBVIOUS flaws. First he goes to say that the SO6P was an uzumaki, just because. That's not an argument. I could say he was an Uchiha who developed the pure rinnengan "just because". His second point, the Sage of Six Path didn't have ninjutsu, is again his own hypothesis with absolutely NO backing from the manga. The Sage of Six Paths is regarded as the father of ninjutsu, their is no manga-text that suggests he only gained this ninjutsu power after he "captured" the Ten-Tails. He then states that nagato is the "spitting image" of the Sage of Six Paths, again with no support from anything in the manga and deriving from his own guess work, and that because Nagato only got his powers after getting the rinnengan, WHICH CAME FROM MADARA, something he fails to mention entirely, he then states that adds credibility to his previous theories. So his entire logic is built upon "X is Y because Z Which is B and it's true 'cuz I say so".
Well, let me disprove everything from the start. The Uzumaki are a BRANCH of the senju. That means that they are not only not fully of one of the Sage's son's bloodlines but are only distantly related too boot. Their is no way that the Uzumaki clan could have existed at the time of the Sage's birth, as the Senju didn't come into being until AFTER he was dead. Secondly, the fact that the sage's son had a rinnengan-like dojutsu means that the rinnengan he had WAS GENETIC. To assume that getting implanted eyes means you are suddenly able to pass on such genes is folly. That's like saying Kakashi and danzo can now have children with the sharingan. Secondly, the Rinnengan only activated for Madara as he had both harishama's DNA AND his sharingan was at their peak. The Uzumaki have absolutely no relation to the Uchiha, which, arguably, the most important piece necessary to activate the rinnengan. So how can the Uzumaki, with no dojutsu, spawn the Uchiha when the Senju are what spawned the Uzumaki, and the senju have no dojutsu, and the both originate from the same person(the Sage of Six Paths).
Anyone who says the Sage of Six Path is an Uzumaki is a retard of the highest order.