In regard to the topic of this thread, I agree that I think Rinnegan shouldn't require Senju DNA, but it has been strongly implied that Madara got access to Senju DNA before he awakened it. That, right there, strongly implies that there is at least a chance rinnegan requires Senju DNA. I used to strongly think that Rinnegan did not require Senju DNA, but now I'm split on the matter, and your post really didn't prove anything additionally to me.
At the very least, Kishi has left things open-ended with how he's handled these issues but the only way it will be confirmed is when Sasuke unlocks Rinnegan for himself, whether he will have senju DNA at that time or not.