Imagine that you are right and a person is on drugs; what kind of inhumane psychopath do you have to be to see someone having a medical emergency - regardless of the cause - and think that the police are the best people to deal with the situation?
You would only have to uncritically believe what you were told growing up by state PSAs, sitcoms, cartoons, teachers, librarians, medical professionals, therapists, other police officers, religious leaders, and probably your parents and grandparents. Every shadow you see on the cave wall tells you that the police are the answer to every problem.