Earth doesn’t, in fact, have a monopoly on mean kids. You can find them in Lunar refugee camps, too.
This can’t possibly be raw Moon gravel that they’re walking on. Real regolith will kill you, tear up your lungs AND shred your feet. It’s tiny shards of glass. I like this gravel for the aesthetics, but let’s assume someone has gone to the trouble of melting it down and reshaping the regolith into a gravel that’s friendlier shapes.
Mars doesn’t have the regolith problem. Dust, sand, and rocks on Mars have been subject to wind erosion for millennia. That’s one more reason for terraforming Mars being easier than trying to live on the Moon.

↓ Transcript
Panel 1: Maida sits up and sees a version of herself standing nearby that's three years younger, from when she was in the fugee camp on Luna, holding a ratty old football.
Panel 2: Flashback to when she was on Luna. Two other girls about the same age approach her. There are tents orderly arranged around them. First girl (speaking Swahili): "Look at that." Second girl: "Hey kid! Where did you get that football?"
Panel 3: Maida: "I... found it in a drainpipe? Is... is it yours? Do you... want to play?"
Panel 4: First girl: "No, I think you should just give it to us so we can play with it." Second girl: Yeah you don't need it. You don't even have anyone to play with."
Panel 5: The two girls and one more kid play at kicking the football around in an empty corner. Maida walks away sadly by herself. Nearby a father and son are cooking something in a frying pan over a makeshift heater.