You're reading too much into what the poster is trying to say, and attaching some kind of baggage to the phrase. The point isn't that only youngsters can enjoy

You're reading too much into what the poster is trying to say, and attaching some kind of baggage to the phrase. The point isn't that only youngsters can enjoy video games, nor that video games are inherently immature, nor that the act of growing up necessitates that someone lose interest in gaming, nor that adults can't enjoy games. The point is that video games are something the poster enjoyed as a youngster but no longer enjoys as an adult. That's all "growing up" means. You could s/video games/*/g, and it would still just be part of "growing up".