I don't see gamers having less friends than non-gamers at all. In fact, it might cause them to make some more due to having a sort of connection or having common ground with other people also involved with video games.
I disagree, gaming makes people cooperate and have fun together. It's the actual opposite in my opinion. Friends aren't always those you can meet in real life.
Yes, I also find the idea that gamers have less friends. Especially since in many cases gaming actually brings a large group of people together, both online and in real life. Where I've gamed with friends of mine many times growing up, even having a LAN party with my local Star Trek Club. Diabo II, Minecraft, WoW, and Quake (Though I wasn't as good playing the last game).
I [don't know]. I didn't have many friends growing up being a gamer. I was kind of always looked at like a weird one I guess you'd say. So I believe this has some truth to it.