When we forget that Sikhi is the only religion that is idea based, NOT personality based as other relgions are, then we start concocting silly stories to justify the existence of Sikhi amongst the plethora of other religions.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/gurmat-vichaar/18511-is-it-true-can-it-so.html

Sikhi needs no justification at all to prove its validity. It is NOT a dogmatic religion based on subjective truths but a pragmatic way of life based on objective reality. That's why it has the universal message.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=18511

Whether Guru Nanak is mentioned in the Vedas or not is irrelevant. If we stop and ponder for bit what names or titles our Gurus gave themselves in Sri Guru Granth Sahib Ji? We have to stop and think,because there are NONE. Just numbers. Which shows us that Sikhi is about the message not about the messenger.

Hence it is NOT about our Gurus but about Gurbani.

Tejwant