All cops are bastards - as well as immoral.

If a law was made tomorrow that all people wearing a green shirt need to be shot, the way cops would act would prove this.

If a cop refused to go along with it, he would prove that laws are not perfect, and he would have every reason in the world to question every other law he has ever followed.

If a cop agreed to go along with it, he would prove that he has no ability to think for himself, and will just do whatever the law makers tell him to - and there's no reason to trust or respect a person like that.