What is a counter example of why child abuse is okay?

True child abuse is never "okay".

The only real life counter example that abuse is hard to stop is the argument that it is cultural and a culture cannot be changed from an outsider.

For example, China's rules about girl babies often means mothers or families kill girl babies. In African countries, girls are subjected to female genital mutilation. In Middle Eastern countries, young girls are still promised into marriage with an older man. In many undeveloped countries, child slavery (boys for work; girls for sex) still occurs in 2016.