Censorship is used to silence dissenting views.  All comments are closed, which means ADN is not subversively promoting those with a different opinion than you.  

Many online news outlets occasionally close comments (or just don't open them) when the content is likely to devolve into racial or bigoted hysterics.  I've even seen it many times on Fox News, of all places, where many comment threads include KKK level nonsense.  Yet some stories elicit threads too vile even for them.

ADN is making an effort to improve the civility of the conversation.  The problem is, some stories elicit a high degree of incivility from otherwise civil citizens.  ADN is taking the easy way out here, but I don't really blame them.  They don't have the staff or inclination to moderate these topics, so they very occasionally take a pass.