What you're really looking for is a forum. A bulletin board, to use the outdated parlance.
They still exist, although there is still a lot of hand-wringing over whether forums are "dying" or not.
Long form journalism won't go away, long form discussion won't go away either.
People come to sites through a shared interest, so frankly, I wouldn't want to discuss economics and politics on Bodybuilding.com message boards. Nor would I want to discuss say, design, on a politics forum.