It is OK to show the faults of Mormonism. However, there were times all I thought about was winning the debate, which didn’t help anyone in the long run. I was better at showing someone why the LDS church was wrong than I was in showing them Jesus Christ in my life.
Both are required, not just one or the other. People who thought they were showing me Christ without confronting the errors of Mormonism just validated my view that Mormons were Christians. Those who confronted me about Mormonism also showed me their concern was because of Christ in their life.
If it becomes purely academic, that is when ex-mormon atheists are born and no one wants that.