What about Jews? Orthodox? Seventh Day Adventists? Mormons? Jehovah's Witnesses? Methodists? Lutherans? etc?
How "wrong" does someone have to be in following God before you declare (from your cathedra) that they are following some other being?
What is particularly odd is those claiming the Triune God have no idea of the history of the councils and the development of the creeds of the Most Holy Trinity of the orthodox Christian Faith.
The take Trinitarianism for granted, little as they know about it, and claim it as their own.
It is, to me, as if someone claimed credit for passing a test they never took.