More than one Green Ninja isn't the problem

I genuinely don't get all the fuss about there having been more than one green ninja. Based on the images found in the prophecy it was pretty clear that there were more things at play than just the green ninja (like the red blue white and black ninjas being present for example). So the idea of more people having worn the green gi in the past isn't that crazy. My worries about all this have to do with the implication that the master of life and the green ninja being the same thing. "The first...