Why is law and order in Los Angeles chaotic?

From the point of view of social security, Los Angeles is very safe. Everyone is polite, obeys the law and is friendly to each other.

But there are good people and bad people everywhere. There are not many blacks in Los Angeles, but there are many Mexicans. As long as you don't wander around at night, you won't be targeted by those dishonest people.

Summary: It's safe and comfortable here.

I don't know the mentality of those who say that in the United States, we should be careful not to let the police shoot at will. In short, this is not reality.