When reading something which is well written and demonstrates a significant point, I don't go to the trouble to do a background check of the author, because I believe facts stand on their own merits regardless of who articulates them.
Lincoln, whether he was an atheist or not, (I believe he was) was a brilliant thinker and writer, and a brilliant manipulator of men. It is this intelligence and ability to manipulate people that made him such a fine lawyer in his day.
Mencken, whether he was an atheist or not, could still write some excellent commentary about the world he lived in during his time.
With Lincoln, pretending to be the wrath of God against the wicked, the matter of his disbelief in God becomes a valid point in arguing that his motives were not so pure as people have been led to believe.
You take away his "God" argument, and what is left but POWER? "Subjugation"?
Mencken was just a newspaper guy. He didn't kill 750,000 people while claiming to be God's sword on earth.
It's funny how the Atheists always end up killing hundreds of thousands of people when they get into power.
The Soviets, the Chinese, the Cambodians, and even the Nazis, were all atheists.
Quotes from Lincoln regarding his faith: