The Book of Mormon contains many warnings that are unpleasant to hear. Its prophetic writers foretold many of the abominations of our day and the wicked who God will punish for their violations of commandments. Many people become angry at such words and writing, feeling that they should not be punished for much enjoyed and celebrated sins.
Everyone can act in whatever way they please. However, they cannot alter the just result of their actions, either good and bad. God through his prophets and their warnings work to make plain the mortal and eternal consequences for our works so that we cannot claim either ignorance or abandonment.
In other words, prophets and apostles work to rid themselves of the blame for the sins of others. They have warned us of this:
And these things are written that we may rid our garments of the blood of our brethren, who have dwindled in unbelief.
I am writing this right now. People will be punished for the sins as written in holy writ and the fleshy pages of our conscious. I am often pointed, to the chagrin of the guilty. I do this so that those facing the fires of hell cannot turn back on me with the accusation "You didn't warn me!" Here I am - warning you. We must all turn to better ways!