Here is my reasoning: if NASCAR is a sport, then why can't FIRST be a sport?
However, not everything in FIRST is a sport. During the build season, the fabrication and programming of the robot may not qualify as a sport. There just isn't any "competition". Without competition, you cannot have a sport. But, at the regionals and Championships, you are competing in a game, against an opponent, with an objective to win. There are set rules and a definite playing field. You can score points, and you can get penalties. There are cheering fans, passionate team members, and hard-core competitors.
All of these are present in traditional sports, so FIRST competitions are no exception. Therefore, I consider competing in the competitions a varsity sport, with the sport being Aim High, Triple Play, or whatever game FIRST develops.