NPR, and in fact all news websites, should have the availability of comments. These comments promote discussion and learning. Certainly the tone can get nasty at times, but NPR could set up guidelines and policies, and delete any comments that do not follow the policy. Comments help to provide news which is balanced as both sides are able to express their views.
NPR can make its own decisions, and if it doesn't want to allow comments, it certainly doesn't have to. I think that being able to comment on articles is a great aspect of internet journalism. It lets readers react to stories and feel more connected to the news. However, I also understand why NPR would get rid of this feature. Internet comments sections are notorious for being filled with rude, hateful comments and insult-filled arguments. I can understand a company wanting to eliminate that. At the same time, I think it is a mistake, especially considering that NPR comments are probably much more polite and intelligent than comments on many other websites. I think that allowing comments, but having moderators who go through and delete rude, inappropriate comments is the correct approach to this dilemma.
A public radio station has a duty to allow the public to comment on its programming, and by removing the comments on its site it has effectively silenced any criticisms those people may have had. The internet may be full of trolls, but restricting freedom of speech online is simply not the way to go.
No, NPR should not be required to do anything. Who would make this requirement? The government? The very idea of NPR is that they are free to broadcast, or in this case publish online, whatever strikes their fancy. Web comments require a tremendous amound of time spent on moderating them to weed out spam and obscenities. If NPR chooses not to spend their limited money on this, yet still post their content to Facebook where comments are abundent, then that should be their right.