[RansomOttawa]

I think what Joel is saying is that anyone who confesses Jesus Christ as their Lord and Savoir is a Christian.

Then Mormons are Christians only if "Christ" is a label, rather than a historical figure. Because the "Jesus Christ" we find in Mormonism is not the one revealed in the Bible and formally defined at the councils of Nicaea or Chalcedon.

[MHGinTN]

Here's an analogous situation, borrowed from Freeper William Clark, illustrating how one can have faith in 'a' Christ but not the true Savior Christ:

"I always like to use the analogy of Jim Caviezel [In Mel Gibson's 'The Passion of The Christ']. Like the Mormon Jesus, he dressed the part, spoke the same words (in the original language, no less), and was referred to as Jesus Christ within a specific context, but it makes all the difference in the world whether one worships and depends upon him for their salvation or the genuine article."

[rzman21]

A lot of Evangelicala reject Ephesus and the definition of Mary as Theotokos, so it’s shaky ground to criticize the Mormons for rejecting ecumenical councils of the Catholic Church.

Evangelical Neo-Nestorianism is every bit as problematic.