Why do many firemen/EMS have such an attitude?

Now, I'm not looking to start any fights or insult people. However, I am very often around people from those professions and have noticed that many of them are pretty arrogant. Why? Many have an attitude of being better than others, and I have firsthand experience of EMS making fun of an attempted suicide victim at the scene. They just act so conceited, as if they are better than "normal" people. I have noticed that this is often more characteristic of volunteers than paid professionals. Yes, I know that they do help the general public. But members of the military are almost never as arrogant as firefighters/EMS. There is a huge difference between pride in an organization and arrogance. Obviously, not all members are like this, but this has become a stereotype to me. So please, help me understand this.