I dunno, I've really enjoyed a lot of co-op games with my friends, from top-down crawlers (I really liked Dead Nation a few years back), to Dota, to the massive, highly organized melees in Planetside 2. When not playing from the comfort of a sofa on splitscreen, I always have my headset.
Anyway, videogames are creative ways for friends to engage at deep, problem-solving levels. They're a lot more socially interactive than, say, TV, or watching a sports game, or watching a concert (all fine social activities in the right context, like anything else).
Granted, as a hardcore gamer even I think people need to spend more time unplugged, for sure.
Mostly I think reactions like yours are becoming antiquated. All emergent media get treated like the red-headed step child (it was weird for me back in undergrad reading polemics against the novel form, claiming that poetry was the only worthwhile written entertainment), so I understand where it comes from, but it's on the wrong side of history.