I guess their point was to balance the times. I.e. Yes, excessive socializing would also be bad if you start neglecting everything else.

Excessive socializing is the default, though - if kids have nothing better to do, they "hang out".

Is it? When I had nothing to do, I read or used the computer (for games, and then increasingly for programming).

Me too. Because I had essentially unlimited screentime. But you and me are the exceptions. Think of people you remember from primary and secondary school.

The clear solution is to jog on the spot, chatting with your friends while watching TV with subtitles on. The ultimate activity.

Perfectly showcasing why trying to do all simultaneously in a "balance" makes you benefit from none of them.

I think this activity is called “Pokémon Go”