However... let me also explore a different perspective on this.
Do you feel the same way about paramedics and firefighters? We choose to put ourselves in harms way for the sake of others. Heroic, right? No... not really... My first priority on any scene is to go home to my wife and daughter at the end of the day. In fact, my priorities (usually...) are me, then my crew, then you.
Firefighting is not without risk, but in reality, modern firefighting is very conservative, and growing more so every year. There are practical reasons for this though. When a cop or a firefighter is out of the fight, they're not doing anyone any good. In fact, they are now causing a division of resources in the operation as they have now become someone else we need to rescue.
I am my first priority because I can't do anyone any good if I'm injured. My crew is my second priority because they are the ones that are going to take care of me if things go sideways. Keeping those priorities straight is what maximizes our effectiveness in preserving life.
I realize this comparison is not perfect (it's generally easy enough to identify fire vs innocent civilians), and I am by no means excusing the military mindset of many modern police forces, but I hope that gives you some insight into the mindset behind some of the tactics used.