It's not blocked, some posts do make it there occasionally. Previously they were able to rocket things to the front page by taking advantage of the fact that Re

It's not blocked, some posts do make it there occasionally. Previously they were able to rocket things to the front page by taking advantage of the fact that Reddit places a huge weight on the first few upvotes, so getting a lot of votes quickly almost always meant making the front page. Reddit had since changed the algorithm so that technique isn't as effective anymore. I would wager they just don't have the actual numbers normally to make the front page without gaming the algorithm. They have lots of subs but there active user count was always very low for the number of subs they have.