Hi David: You really shake the trees!  I think the people who wrote you how WONDERFUL and MEANINGFUL it is to understand that they and life have no meaning, don’t really believe it.  We all think our lives are important or we become despondent and suicidal.  There is much nihilism in the world that turns to the black because they do despair at the perceived meaninglessness. But people who are happy and fulfilled by it, are either whistling past the graveyard or fooling themselves.

As to us being a moral species, that is true in the sense that we are hard wired to believe and at least in some fashion perceive right and wrong, even if that is a fluid concept. That doesn’t make what we believe moral.
 
I don’t know why I think this is relevant, but I do: When I took acting lessons during my Hollywood days, Guy Stockwell, my teacher, told me that one key to playing a good villain is that he doesn’t think he’s the bad guy.  He may know he has broken laws or done something that can get him in trouble. But he thinks he is justified.  
 
The only real exception to that is Joker in the most recent Batman movie.  A very interesting character.  He wants everyone to be complicit in his evil. He wants to prove that our society is as off the rails as he is and we are all, underneath our pretensions, like him.  But then again, he doesn’t see himself as the bad guy, he sees us as the bad guys because of our phoniness and pretense.