The conclusion of this whole matter concerning half-truths is this. Every word and doctrine in the scriptures reveals one person and that is Christ, who created all things, who is before all things and by Him all things consist ... that He might have the preeminence / Col 1:13-22. Any doctrine that is taught from the scriptures must reveal the One who has the preeminence. If it does not reveal Christ, His nature, His attributes, His character, His justice, His love, His light, His life, His redemption and the cross of His death, burial and resurrection ... then it does not come from Him nor does it glorify the Father. This kind of doctrine that does not reveal Christ should be rejected completely, no matter what form it comes packaged in.
If we have the Holy Spirit dwelling in us, the Spirit of truth that comes from the Father / Jn 14:17, 15:26, and we have the word of God is abiding in us / Jn 15:7 then we will know the spirit of truth from the spirit of error because we are of God and those that are of God heareth us / 1Jn 4:6. That is quite a bold statement of truth isn't it, and nothing half-baked about it either. Those that are not of God do not have the Spirit of truth and can not hear the truth nor the words of truth and do not bear witness of the truth / 1Jn 5:6, Jn 15:27, Jn 18:37, neither are they of the truth / Jm 1:18. Every word and doctrine they teach is not of the truth because it does not reveal Christ / 1Jn 4:2,3, 2Jn 1:7.
So why should we who are born of the truth and have the truth in us through the word, through doctrine and through the Holy Spirit that abides in us, be concerned about the half-truths of those that are not of the truth and who live in a lie? They not only live in a lie without the truth but have no capacity to do the truth and that makes them a worker of iniquity. A worker of iniquity is one that has set themselves against the authority of what God has established as truth through His Son. When iniquity was found in Lucifer there was no truth in him and he was a murderer from the beginning / Jn 8:44.
We that are of the truth should have nothing to do with those that work iniquity and have not the truth. They abide in a lie and they have not the love of God in them. They can not love the brethren therefore they hate the brethren because they do not have the love of the truth / 2Thes 2:10. We know that we have passed from death unto life because we love the brethren, but those that do not love the brethren are murderers and we know that a murderer has no eternal life abiding in him / 1Jn 3:15.
God does not only say that they live in a lie without the truth but are murderers without eternal life. That's heavy duty but it puts them in their place in relationship to the truth, who is Christ in us. I do not see God being very concerned with those that have not the truth, who can not hear or speak the truth and live in a lie. Those that ascribe to or compromise in any way to the doctrines of LDS or any other faith that have not the truth are unwise and show a heart that is sympathetic toward lies and a heart that does not love the brethren.
Jn 8:42-47
42 Jesus said unto them, If God were your Father, ye would love me: for I proceeded forth and came from God; neither came I of myself, but he sent me.
43 Why do ye not understand my speech? even because ye cannot hear my word.
44 Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.
45 And because I tell you the truth, ye believe me not.
46 Which of you convinceth me of sin? And if I say the truth, why do ye not believe me?
47 He that is of God heareth God's words: ye therefore hear them not, because ye are not of God.
Is not that the truth?