The LDS Church doesn’t teach anything about it, they let the BYU historians write and argue to their hearts content. Ya know these guys have to publish to stay relevant.
Who knows what is in someone’s heart. I think most people leave any organizations for many reasons and not just one. A man will let one thing really tick him off and anger builds. Then he starts looking for more faults to justify his rebellion.
With Oliver there were 9 different charges brought against him by the council. One point in his excommunication was Joseph’s first plural marriage, it did not sit well with Oliver and he had said things that others took as seditious. Then there were these two points which probable were part of his real problem, being that he was a lawyer.
"Fourth-For virtually denying the faith by declaring that he would not be governed by any ecclesiastical authority or revelations whatever, in his temporal affairs.
"Fifth-For selling his lands in Jackson county, contrary to the revelations.
As with Ananias and Sapphira in Acts 5 Oliver not have his heart into having all things in common. At the time this Law of Consecration was given and even now it part of the covenants we make. Oliver was unwilling to abided by the covenant and so separated himself from the Church, the excommunication was just a formal severing of his baptism covenants etc.
Here is what Oliver wrote; First remember he’s a lawyer and sceondly Jesus taught the rich man “sell all that thou hast, and distribute unto the poor, and thou shalt have treasure in heaven: and come, follow me.”
“I have no disposition to contend with the Council....the three great principles of English liberty, as laid down in the books, are 'the right of personal security, the right of personal liberty, and the right of private property.'....they are so woven into my nature...that I am wholly unwilling to exchange them for anything less liberal, less benevolent, or less free.
"The very principle of which I conceive to be couched in an attempt to set up a kind of petty government, controlled and dictated by ecclesiastical influence, in the midst of this national and state government. You will, no doubt, say this is not correct; but the bare notice of these charges, over which you assume a right to decide, is in my opinion, a direct attempt to make the secular power subservient to Church direction-to the correctness of which I cannot in conscience subscribe-I believe that principle never did fail to produce anarchy and confusion.
"This attempt to control me in my temporal interests, I conceive to be a disposition to take from me a portion of my Constitutional privileges and inherent right-I only, respectfully, ask leave, therefore, to withdraw from a society assuming they have such right.…”
Oliver’s property meant more to him than listening to the man he knew had seen and spoken to Jesus, he had been at Joseph side for several different vision.
You said "Maybe what happened to these three show that the followers of Smith were not loyal, so when Smith claimed his church were more loyal to him than Christ, he may have lied or been very, very deluded!"
The story of Oliver reminds me Peter in away, while pressed about being Jesus’ friend he let the world frighten him and he denied the his Savior and friend.
Now after Joseph was killed it seemed to move Oliver like Peter to repentance.
There is a letter George A. Smith wrote to Orson Pratt, 31 Oct 1848,
“…Oliver Cowdery, who had just arrived from Wisconsin with his family, on being invited, addressed the meeting. He bore testimony in the most positive terms of the truth of the Book of Mormon--the restoration of the priesthood to the earth, and the mission of Joseph Smith as the Prophet of the last days; and told the people if they wanted to follow the right path, to keep the main channel of the stream--where the body of the Church goes, there is the authority; and all these lo here's and lo there's have no authority; but this people have the true and holy priesthood; "for the angel said unto Joseph Smith, Jr., in my hearing, that this priesthood shall remain on the earth unto the end." His testimony produced quite a sensation among the gentlemen present, who did not belong to the Church, and it was gratefully received by all the Saints. Last evening (Oct. 30th) President Hyde and myself spent the evening with Brother Cowdery. He told us he had come to listen to our counsel and would do as we told him. He had been cut off from the Church by a council; had withdrawn himself from it; stayed away eleven years; and now came back, not expecting to be a leader, but wished to be a member and have part among us. He considered that he ought to be baptized; and did not expect to return without it. He said that Joseph Smith had fulfilled his mission faithfully before God until death; he was determined to rise with the Church, and if it went down he was willing to go down with it. I saw him today, told him I was going to write you. He sends his respects to you; he says, "Tell Brother Orson I am advised by the brethren to remain here this winter, and assist Brother Hyde in the printing office, and as soon as I get settled I will write him a letter." I remain, as ever your brother in the kingdom of patienc..”
He actually died a short time later with what seems to be Tuberculoses.
There are these recollections of those who were there at his death bed;
Elder Phineas H. Young, who was present at his [Oliver Cowdery's] death [at Richmond, Missouri, March 3, 1850] says, "His last moments were spent in bearing testimony of the truth of the Gospel revealed through Joseph Smith, and the power of the holy priesthood which he had received through his administrations." [See MS 21 (1859):545.]
Oliver Cowdery's half-sister, Lucy P. Young, widow of Phineas H. Young, relates that Oliver Cowdery just before breathing his last asked his attendants to raise him up in bed that he might talk to the family and his friends who were present. He then told them to live according to the teachings contained in the Book of Mormon, and promised them if they would do this that they would meet him in heaven. He then said, "Lay me down and let me fall asleep." A few moments later he died, without a struggle.
David Whitmer testified to Apostles Orson Pratt and Joseph F. Smith in 1878, as follows: "Oliver died the happiest man I ever saw. After shaking hands with the family and kissing his wife and daughter, he said, "Now I lay me down for the last time: I am going to my Savior;" and he died immediately with a smile on his face.
Life of Oliver Cowdery
Now on friends being loyal.
When the Jewish leaders came to arrest Jesus his apostles scattered in fear,
“But all this was done, that the scriptures of the prophets might be fulfilled. Then all the disciples forsook him, and fled.” Matt 27:56
Peter alone followed from a distance and then denied him. As He hung on the cross the only one there was John and a few women.
When Joseph Smith was facing his death he literally had to send people away. John Taylor, Willard Richards, John Fullmer, Dan Jones, Stephen Markham, Cyrus Wheelock, his brothers Hyrum and Samuel Smith, and his uncle John Smith all went with him to Carthage. His aged Uncle braved walking through the mob to gain entrance into the jail. All of their lives were threatened by the mob but they still stayed with Joseph until he sent all but four on errands and then they were not allowed back in.
You might not know this but Samuel Smith was also wounded on that day. He had gone home to his wife and family and was the first to hear the news of his brothers deaths. He jumped upon his horse and dogging bullets rode as fast as he could to the jail. He stayed all night with the bodies. It is felt because of the description of his illness that somehow as he bent over the saddle horn to doge the bullets and riding as fast as he did he damaged his internal organs. He died a month later. Lucy Smith lost three sons within a month of each other.