The same way the problem with the police apply to all the police or racism applies to all white people.
It's a question of material interests. The system of domination creates material benefits for the dominant classes that enters in contradiction with the interests of the dominated one.
In the case of the police, it's a form of power and instutionnal recognition.
In the case of white people, it's the status of whiteness
In the case of adults, it's a power of domination an exploitation
These interests are shared by ALL members of said class and enters - by nature - in conflict with any kind of understanding or action against said domination systems. Which means that no matter how much antiracist you are, if you are white and racism never completely disappeared, you will have biases and interests that will counter your antiracism. Which is something all white activists must have in mind.
This is why racialized people, when they need to express themselves completely, will prefer spaces without mixity, because they won't have to face the racism that is still present in antiracist.
"Child abuse" would not be sufficient as it doesn't name the real problem : which is the domination of adults.
This is why racism is called "racism" and not "discriminations against black people" or patriarchy is not called "sexism against women". The names are pointing the fundamental issue which can help us to extent the analysis to various degree of dominations, exploitation and abuse.