Knife Attacks on children in schools in China

If it is an older male attacking children with a knife in China it is usually because this man was Middle or lower class and could not have a wife and children because there aren't enough women to marry in China. So, only wealthier men have wives and children because of being allowed only one child so female children were often killed as babies between the 1970s and a few years ago when this changed somewhat. However, if China had not done this instead of 1.4 billion people now they would have had now 5 to 8 billion people now instead. So, the financial success of China instead of being a complete disaster which could have caused human extinction on earth was tied directly to only allowing 1 child per family all those years.

Trying to understand why a female would attack children in a school could be a mental health problem or it could be possibly because this woman wasn't ever allowed to have children for one reason or another and it finally drove her insane or it could have been that she was forced to be sterilized which also can happen in China in many different situations over the years.