* allow them to demonetize / ban / block videos for abuse of categorization
* train machine learning on the various categories
It's a lot more socially palatable for Youtube to say "Hey guys, we HAVE a blood and violence category, but you didn't use it for this video. So we'll punish you for that."
Instead, we get programming videos getting demonetized / blocked for god only knows what reason. That makes people made, and is bad press.