No more than a Christian who claims that Jesus is not God, can not claim to be a Christian. They can claim to be a Christian all they want to, that does not make it so.
Your view is why Arian
Christians were violently oppressed following the Council of Nicene.
Many early Christians believed Jesus was the Son of God, but not God Himself, as
many Christian scriptures seem to imply that fact (Luke 22:42: Father, if you are willing, take this cup from me; yet
not my will, but yours be done.).
At the very least you would have to admit that for early Christians, especially those without access to the Book of John or knowledge of its interpretations, it would be a pretty easy assumption to make that Jesus and God were separate.
So you are saying all those early devotees of Jesus, all those who followed his Word, all those who were even unaware of the very few Scriptures in John that even hint at a trinity, all of those people who suffered and even died for their belief in Christ, all of those martyrs and saints, but who merely did not believe in or were unaware of the interpretation of the Book of John that says Jesus is literally God,
were not real Christians??
Sorry but I find your views there abhorrent.