This isn't true though. CNN/NYTimes/etc can't be sued for 3rd party comments on their site. CNN is also allowed to filter what comments make it on their site. These are not opposing ideas.
I grew up reading the NYTimes online and thought that the discussion section offered great debate. I think it might have become a case of it is too expensive to moderate? Do people just post ads and spam? Because in my mind, active discussion is always good