Him opening himself up to the world to share his "thoughts" and receive criticism is gonna make him a much wiser person the older he gets. Some of his views will change as he matures and the beliefs that he continues to hold true will no doubt be because he's gained the life experience needed to substantiate them. Now if he had some of these thoughts and didn't share them, I'd be more concerned.
Most kids his age have similar thoughts but they are too embarrassed to share them. I always tell my kids "tell me whats on your mind and if you think it's stupid, at least give me the opportunity to tell you its stupid, but don't let that be the reason you don't share". One of the best gifts you can give a child is perspective. And the more freedom they have to share their thoughts, the more opportunity you have to provide perspective.