You can't label someone that plays Cod a '12 year old kid with no friends that is a tryhard' or someone who plays an MMORPG (Wow/Runescape etc) someone with no life, no friends etc.
People have time in their lives to play those games, so they play them, it's just when they get
addicted it is a problem, and that is what makes them lose friends and make a game their priority and that, but there are some that just play casual and to a limit, if you can't leave a game for something, eg friend invites you over or something, then most likely you are addicted.
I used to be addicted to play a few games too much, but I've grown up, I used to play Cod and care too much about K/d, getting to that killstreak etc, but now I just run around and shoot rpgs at people, jump around, shoot people, troll etc and have an awesome time, when you buy a game for whatever they cost (about $100 in Australia) get the most out of them. Rpgs are the only games I take seriously, eg Mass Effect,Fallout etc because if you do stupid crap you pretty much fail the game, but with shooters have fun, when people say'relax it's just a game' just learn to relax.
But if you have fun camping for a whole game on cod, acting like a tryhard, running around taking the game too seriously and raging when you die, then do it, if you don't, keep doing it because I will enjoy hearing you rage, because I get the most out of the games I buy
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tl;dr version:
No game is nerdy, just the people that play it and take it too seriously