36 Now these dissenters, having the same instruction and the same information of the Nephites, yea, having been instructed in the same knowledge of the Lord, nevertheless, it is strange to relate, not long after their dissensions they became more hardened and impenitent, and more wild, wicked and ferocious than the Lamanites—drinking in with the traditions of the Lamanites; giving way to indolence, and all manner of lasciviousness; yea, entirely forgetting the Lord their God.
The most vocal opponents of the restored gospel are those who once accepted the truth. When you turn away from the truth, you have to justify your actions to yourself in some way or just not care. Some leave the fold due to apathy, but they rarely become active opponents. But those who engage in sin and seek to justify themselves in doing it often rage against the church and condemn its peaceful practitioners. All are free to believe as they choose. So, those who seek to tear down any faith should ask themselves why they feel it necessary to do that. Attacking the beliefs of others does not confirm the truth of my own beliefs.