Oh christ, here we go again. Is x a sport? Where is the line between a game and a sport? Or a sport and a hobby? The same fight has plagued the Olympics for decades. Lately, the same argument has been used against talented video game players. "Video games are games, not sports; you can't be a cyberathlete. It's just a game."
The only thing this study showed (not proved) is that video games don't improve physical health factors like strength and aerobic endurance, which isn't surprising to anybody (whose parents haven't said, "Get off the couch or you'll end up lazy and fat."). What it did show is that video games improve your reaction times and strategic thinking just like sports, which is what video game players have been trying to argue for years.
Any activity which challenges our abilities will make us better at those activities. Sports like football and hockey require a lot of physical abilities as well as team work, strategy, reactions, perception, and prediction. Though few (if any) video games require physical abilities, most involve all of the other same abilities.
Want to know what other "sport" doesn't require physical feats but does challenge strategy, reaction times, perception, and prediction? Car racing. Somebody please tell Michael Andretti and Dale Earnhardt that they "will never be confused with actual athletes."
If somebody wants to argue that video games aren't a replacement for sports (in the context of helping young people develop and adults stay healthy), because they don't involve physical activity, then all the power to them. But if they want to use it to isolate gamers, making them seem somehow less worthy than athletes, they can go piss up a rope. Video games are challenging in many of the same ways as sport and anybody who can attain the levels of perfection that pro gamers can is still worthy of admiration for the same reasons as pro athletes. It ain't easy being that good.