There's a weird perception that's floating out there claiming that video gaming cannot be "a sport", just because it's more mental than physical (although even that varies per game, for example high-level Guitar Hero players require extreme endurance and stamina). I also would wager a non-zero percentage of people with such mindset would also deny that chess is a sport, unless they grandfather it in due to the sheer age of chessdom.
It doesn't help that there is a partially overlapping mindset that believes that video games are for kids, something to grow out of. Since the vast majority of competitive gamers at the extreme top end are young adults, that theory is incorrect, but those who happen to be in the center of that Venn diagram would probably also deny that successful Twitch streamers have a "real job", etc.
The surprisingly emotional debate of "is it a sport or is it a game" has been around from the moment we invented the category of "sports". I don't think it will ever be definitively settled, because the difference is cultural, not technical, and cultural attitudes change with time and location.
Personally, the technical-ish definition that makes the most sense to me is "if it's a competition and people are gathering to watch it without participating, then it's a sport".
I don't consider those sports. They are mostly games like darts. Competitions that are won by arbitrary judging are their own category of thing. I know fighting sports are judged when there is no KO or concession, but that's why they say don't leave it to the judges because that is not a true win.
This doesn't strike me as that weird. Playing a guitar also takes extreme stamina, for instance, but it takes a great deal more technical skill to hit the rhythmn and fingering. (Or at least if that isn't the case, that's certainly the perception.) Many guitarists also write their own music, and the truly impressive ones improvise.
Many sports require full-body coordination. I would also consider, say, a skilled ballet dancer much more obviously impressive and intriguing than being the best video gamer in the world. The only reason one might not consider it a sport is that it's not as competition-oriented (and I may be completely wrong in that; I can't feign deep knowledge of ballet).
I don't think it's disparaging to not consider video games a sport, either, it just seems like a category error. Much of the skill is simply not visible to people not intimately familiar with the game, the mechanics, and what might be difficult about it. I would put it in the same category as, say, live coding, or watching an expert artisan at work. I also can't fathom, say, the skill it takes to operate a crane as a world-class expert, or ice carving, or fixing a mechanical watch, or blowing glass.
Frankly, I also don't consider most streaming to be a "real" job. But that's probably related to the fact that I don't respect most content that emerges. But you could say the same thing about podcasting, or being an opinion columnist, or a pundit/talking head. This doesn't mean it doesn't take skill or effort; I just think it's not producing much of value.
Guitar Hero also isn't directly comparable to guitar. It's more like piano if anything. But the key point is that it brings a tiny fraction of the feeling of playing guitar to people who are completely tone deaf.
The magic of Guitar Hero is that it does bring a semblance of that performance feeling to non-musicians. If what I feel while playing GH is even 1/1000th of what a real musician feels when they perform their music, then holy shit. It gives me a much greater appreciation for what musicians actually feel when they're performing.
"Esports" is not a league. That would be like saying "sports" is a league.
There are leagues around some games (like the ones mentioned in the article). There are also events with "league" in the name that are not really leagues (like ESL Pro League). In any case, none of them are financially successful in the US.
