Enforce but Don’t Obey the Law?

I am confused why people that enforce the law, don’t have to obey the law. It seems odd to me that you take an oath to protect people, but if you are young and not wearing a mask and pull a senior citizen over, you might kill them because you are not following the law. 

I also find it odd that people can drive illegally because they have a badge, that they don’t have to follow the law. I thought speed limits were for everyone. If there is an emergency, shouldn’t an officer use lights on the road, not tailgate people to intimidate? 

And can you protect yourself, no. If you protect yourself, you commit a crime. You must not fight back against criminals, because they are mentally ill or socially disadvantaged.