https://www.theguardian.com/us-news/2020/jun/15/outrage-vide...
It is extremely hard to react with anything but EXTREME vitriol to comments like yours - police are using excessive force deliberately, and then arresting people with no cause who post videos of their crimes.
Without more context, I'm guessing their parents took them to a protest and acted illegally. If so, I think that's rather poor parenting.
There doesn't seem to be a link to the full video (or any video), so take that with a grain of salt.