Gamer and gamers are a great scapegoat for issues that the news media would rather not talk about. For instance whenever a tragic mass shooting happens in the US, many stations, and especially the Fox News channel will try to find evidence that the person who committed the crime was a gamer. If you're wondering why Fox does this more than the other channels it's because they have special interests and pander heavily towards organizations like the NRA. Because of this Fox isn't going to want to have a serious discussions about guns and gun control in the U.S. (I'm not trying to say that guns cause all the problems, there are many good arguments I've seen about how a lot of it can be linked to the U.S. abysmal mental health care.) I actually don't take it as an attack on my hobby when the news media go after games, because usually it has to do with similar reasons.
In terms of general TV shows though. I think it comes from the writers of the show being incredibly out of touch with them. The reason they'll use CoD and Flappy Bird as "hardcore" is because they are incredibly popular. Games are a medium where you really have to care about them to understand which games are truly looked at as amazing, nobody at a TV writers room is going to know about Half-Life or Starcraft.
Although to defend CoD, the people that are good at that game are REALLY dang good at it, and it deserves the good treatment gets from sponsors. I wouldn't quite compare it to something like CS:GO, or even games like DOTA. 2, but I would still call it a hardcore game.
