You’re right, maybe adolescents would have been a better word. “Child” can be meant as developmentally before puberty (which wouldn’t fit here), but in most English countries it also has a legal meaning of being under 18 (or 21) years old - that’s what I had in mind.

The participants of the protests are mostly underage and objectively lack the many privileges and rights of autonomy which our society awards older people. That they protest despite that is all the more impressive.