Well, it's kids playing make-believe, and in a physically active way, I'm all for it.
“If someone says we are playing, it strips away everything we made, it strips away the reality,” said Ms. Aarniomaki. it looks like playing to me as well, and not sure why the community would see that as a problem. even professional sports players know they are playing a game. an interesting and unusual perspective for sure.
https://en.wikipedia.org/wiki/Professional_wrestling
"The matches have predetermined outcomes[11] to heighten entertainment value[12] and all combative maneuvers are executed with the full cooperation of those involved...These facts were once kept highly secret but are now a widely accepted open secret. To promote and sustain the willing suspension of disbelief by maintaining an aura of verisimilitude, the performing company avoids discussing the true nature of the performance in official media"
And these are adults.
These girls may continue their hobbies in adulthood too (like most people keep playing the games they like at older age...)