They never fought Kaguya... If Hagoromo knew that, his flash back wouldn't have been for the Juubi form only. We later learned Kaguya is the Juubi essentially. They only fought the form we saw in the war. They never fought Kaguya herself, who is far stronger in her human form. When they sealed, it was the Juubi's beast form. Unless you're telling me that Hagoromo created the moon twice, once separate from when him and Hamura did it, then you're factually wrong and I'm correct.
They did fight
You must be registered for see links
. Kaguya was the
You must be registered for see links
at that time, but Hagoromo and Hamura
You must be registered for see links
. The
You must be registered for see links
was turned into the core, which is what
You must be registered for see links
did after Kaguya/Juubi was sealed into him and his brother. There wasn't multiple moon events, just one. Kaguya or the Juubi prior to being sent to the moon was just
You must be registered for see links
, although nothing has said what ever happened to Hamura's portion.