Mormons are not christians.
Do they not believe in Christ? Or are Catholics not Christian enough to be Christian either?
Ok, let’s just say Mormons are Christians who have shipwrecked their faith by believing in condemnable doctrines.
1Tim 1:19-20 “Some have rejected these [teachings] and so have
shipwrecked their faith. 20Among them are Hymenaeus and Alexander, whom I have handed over to Satan to be taught not to
blaspheme.”
---
And we christians DO have the authority to judge doctrine:
1Thes 5:21-22 “
Test everything. Hold on to the good. 22Avoid every kind of evil.”
But, I also use the same measure when judging my own beliefs so that I will not be disqualified from the prise:
1Tim 4:16 “Watch your life and
doctrine closely. Persevere in them, because if you do, you will save both yourself and your hearers.”