It is a question of being a destination vs. being another media.
Most of the sites disable commenting because they are publishing newsy stuff which may not bring engagement. Media sites are dependent on social for distribution - they aren't a destination site.
Removing commenting is part of the same strategy - i.e you anyways know that they won't be able to attract quality comments. People are going to share/comment on their social because for then, their commentary on social media will drive much more authority (for personal profile) than commentary on a site.
Media ! = Destination.
Case in point : When we were media, we didn't have so much of engagement. Quality of comments/discussions weren't really amazing!!
The day we switched to a destination platform, it's an altogether different story.
Media != Community.
Community is a different game and needs a different syntax/format.