Why is Jesus being Michael the archangel even a subject that comes up?
It's one of those givens.
Gen 3:15 says the seed will crush the serpent which is the devil. The seed is Jesus.
Jesus said in John 14:2 "for I am going my way to prepare a place for you"
His going to prepare a place was his casting out Satan and his demons.
Jesus did the things stated in Rev 12:7-9 Battled with the dragon/devil and cast him out.
Four names are used for the devil in there, dragon, original serpent, devil and Satan.
Did it need to explain that this Michael was Jesus?
If Michael is not Jesus, why is someone else doing what Jesus said he would do, (prepare a place for his apostles) and battle and crush the devil?