Having debated with anti-mormons, pantheists, agnostics, atheists, etc, I understand your frustrations. There was one time I got so stressed because I couldn't find the answers to a question that was posed. I got caught up in trying to prove our point of view to this group of pantheists who decided to take on the veracity of the Book of Abraham as well as some others who made some hard claims about Joseph Smith. I was reading one day "Seeking the Spirit," By Joseph Fielding McConkie and in the first chapter he says we have no obligation to prove our testimony to others. He uses the example of one offering money to pay a debt. He says if any question of the validity of the money being used is made, it is up to the one receiving the money to prove\disprove its authenticity. The same, as we bear testimony to others, the burden of proof is on them, because you already know. Once I read this, my stress went away. God has not explained everything, and neither should we have to. We Latter-Day Saints, for the most part, are not great theologians or debaters. We are witnesses of the restored gospel in these latter days. In any debate, there comes a time where we simply say "I know by the power of the Holy Ghost." Once we bear testimony, it is up them to prove we didn't experience what we did to earn that testimony. That, is impossible to do. But, in my experience, if someone criticizes the Church and demands proof of something, the last thing they want is proof.