The problem is the word "athlete". We should be using "competitor". One who participates in competitions. Then it doesn't matter if it's an athletic competition or a gaming competition or any other kind.
From the point of view of the government, these types of people are pretty similar. They travel a lot, spending a short time at each destination. Their earnings are uneven, and come in the form of prize money or endorsements. So the government can treat them them the same for the most part, rather than making special rules for each type of competition.
But unfortunately the government calls them "athletes" because athletes were probably in mind when the laws and regulations were being drafted.