Practitioners of the art form can be called doomers.
A recent example of the artform was a discussion of a lake of oil under the waters (but above the bottom) of the Gulf of Mexico, and talk about a huge bubble of methane gas just waiting to break the surface and poison all the coastal communities. Doomers who spun this ignored the physics of how oil and gas actually behave in water, and the way methane can kill (by replacing oxygen in the air around you, but not actually poisoning you like say, chlorine gas does), but those who love doomerporn wailed and shivered in delight.
I have to admit, there have been times I have temporarily succumbed to the right form of doomerporn, but my excursions tend to be brief and sometimes, somehow, good sense and an appreciation for reality usually take over....
This is of course, related to the term Doomgasm.