The parent said they were accused of cheating at a game because they played it enough to perfect it, which isn't something humans can achieve with chess. Even the best chess engines don't play perfect chess, they just play at such a high level that no human can beat them.
At any rate, a 19 year old ranking a couple hundred points below the world champion for the past decade isn't going to have enough practice to use that as an excuse. So no, it's not the same thing.
Outlier players exist in every game, probably because of normal distribution.
Federer for tennis, Carlsen for chess, Serral for SC2 and dorkwood for his game.
The only way to certify their level is through strictly controlled competitions. eSports and chess do the same.
At any rate, a 19 year old ranking a couple hundred points below the world champion for the past decade isn't going to have enough practice to use that as an excuse. So no, it's not the same thing.