Many of the martial artists whom I know began training for purposes of self-defense. Some began as adults, and some were placed in training by their parents after being bullied.
> cycling
That's totally out of the scope of this conversation; I made no claims as to the seriousness with which cycling ought to be treated. I think most sports are given too much credence.
>> It's also exercise
> Aren't those equally true of this hobbyhorse-dressage?
No, not from the gif of a "competition" at the top of the article. It does not appear to contain any serious exertion.
Most sports involve pushing yourself physically. This does not involve such exertion and improvement. If kids want to do it, that's fine (all though still weird as all getout). But I don't think them saying to not "say they are playing" because it "strips away what we've made" is really reasonable. Kids are playing dress-up; it's fine to remind them it's just dress-up. And it's ridiculous to compare it to real sports.