Sadly people sin, racism is a sin and people commit it even if they do not realize it because of the social situation and history they might have been taught. This does not excuse one from the past, but it must be considered. If we are going to excommunicate all that were racist we are going to have to loose many, many otherwise good Christians; so we cannot simply blame LDS leaders or Prophets alone. Martin Luther was virulently anti-Semitic in writings, as were many other Christians through the ages and we are not going to excommunicate them or say they were not Christians (well, maybe the Catholics would excommunicate Luther, but for different reasons

). The ancient Jewish prophets themselves discriminated against Gentiles and kept slaves. Time and place are factors that must be considered, racism and slavery are an evil and have no place in this world we live in today and the LDS leadership has spoken out against it unequivocally.
There is a difference between what you wrote(other than Luther
On the Jews and Their Lies ) and hate towards others. One who is a Christian does not walk or live in sin continually.
Based on First John, those who taught the curse of cain and thus hated their fellow man, do not walk in the light.
In Fact, Joseph Smith's hate is even in the BoM itself.
The question about individuals is just a rabbit trail. There is a difference between the average person and a church leader or so-called prophet.
Alma 3:6 “And the skins of the Lamanites were dark, according to the mark which was set upon their fathers, which was a curse upon them because of their transgression and their rebellion against their brethren…”
3 Nephi 2:15 “And their curse was taken from them, and their skin became white like unto the Nephites;”
3 Nephi 19:30 “And when Jesus had spoken these words he came again unto his disciples; and behold they did pray steadfastly, without ceasing, unto him; and he did smile upon them again; and behold they were white, even as Jesus.”
Note: the real Jesus was Jewish, not white. LOL
2 Nephi 5:21 still says:
“And he had caused the cursing to come upon them, yea, even a sore cursing, because of their iniquity. For behold, they had hardened their hearts against him, and they had become like
unto a flint; wherefore, as they were white, and exceedingly fair and delightsome, that they might not be enticing unto my people the Lord God did cause a skin of blackness to come upon them.”
Joseph Smith himself:
Having learned with extreme regret, that an article entitled, 'Free People of Color,' in the last number of the Star has been misunderstood, we feel in duty bound to state, in this Extra, that our intention was not only to stop free people of color from emigrating to this state, but to prevent them from being admitted as members of the Church.
History of the Church, 1:378-79
Had I anything to do with the negro, I would confine them by strict law to their own species and put them on a national equalization.
History of the Church, Vol. 5, pp. 218-19.
In the Messenger and Advocate (vol. 2, no. 7, p. 300, April 1836), Smith declares that slavery was ordained by God and consistent with the gospel of Christ.
“…we unhesitatingly say…the project of emancipation is destructive to our government, and the notion of amalgamation is devilish!-And insensible to feeling must be the heart, and low indeed must be the mind,
that would consent for a moment, to see his fair daughter, his sister, or perhaps, his bosom companion, in the embrace of a Negro!
We entreat our brethren of the Eastern, the free States, the Canadas, and all, wherever they may be found, not to be surprised or astonished at this step, which we have thus publicly taken: were they acquainted with the present condition of the slave, they would see that they could not be freed, and we enjoy our present, civil and social societies. And further, that this matter cannot be discussed without exciting the feelings of the black population, and cause them to rise, sooner or later, and lay waste and desolate many parts of the Southern country.
This cannot be done without consigning to the dust thousands of human beings. And the bare reflection of being instrumental in causing unprovoked blood to flow, must shock the heart of every saint.”
What is the "Mark of Cain" in the Book of Mormon?
Moses 5:40
"And I the Lord set a a mark upon Cain, lest any finding him should kill him."
But what was this mark?
"For behold, the Lord shall curse the land with much heat, and the barrenness thereof shall go forth forever; and there was a BLACKNESS came upon all the children of Canaan, that they were DESPISED AMONG ALL PEOPLE." LDS Pearl of Great Price, Moses 7:8
Alma 3:6-9
6 And the skins of the Lamanites were dark, according to the mark which was set upon their fathers, which was a acurse upon them because of their transgression and their rebellion against their brethren, who consisted of Nephi, Jacob, and Joseph, and Sam, who were just and holy men.
7 And their brethren sought to destroy them, therefore they were cursed; and the Lord God set a amark upon them, yea, upon Laman and Lemuel, and also the sons of Ishmael, and Ishmaelitish women.
8 And this was done that their seed might be distinguished from the seed of their brethren, that thereby the Lord God might preserve his people, that they might not amix and believe in incorrect btraditions which would prove their destruction.
9 And it came to pass that whosoever did mingle his seed with that of the Lamanites did bring the same curse upon his seed.
So, according to the Book of Mormon, not only is dark skin a curse, but interracial relationships are too!
Even more interesting is the changes made. Compare the Book of Mormon (1830 edition), 2 Nephi, Chapter XII, p. 117
"And the Gospel of Jesus Christ shall be declared among them; wherefore, ...their scales of darkness shall begin to fall from their eyes; and many generations shall not pass away among them, save they shall be a white and delightsome people."
With the current "translation" of 2 Nephi 30:6
"they shall be a pure and a delightsome people."
Why change "white" to "pure?"
What, according to the Book of Mormon, was the "Mark of Cain?"
The Book of Mormon - What is the "Mark of Cain" in the Book of Mormon? (showing 1-50 of 66)
Changing World Chapter 10 Part 1
Curse of Cain? Racism in the Mormon Church Part Two
White and Delightsome or Pure and Delightsome? – A Look at 2 Nephi 30:6
Mormon quotes on blacks
Blacks and the Mormon Priesthood
Are Racist LDS Scriptures Still Deemed “Utterly Reliable” and “Pure Truth”? Part 1 | Mormon Coffee
Joseph Smith Founder of LDS Racist Scriptures and Teachings: Part 2 | Mormon Coffee
Brigham Young's Speech on: Slavery, Blacks, and the Priesthood
google Joseph Smith 1830s "mark of cain" statements