1. Response was proportional. Man on bike pulled over for not having a light at night...Safety issue. When stopped, man ditches bike and runs...So, according to you, ah well, too bad, guess that one got away right? Wrong! That's not how police react to someone running, and not how they should react to that.
2. Police have the right to go into, or through your yard in the pursuit of a criminal running...That is just a fact. And, I'll go one further, if the police are chasing someone who ran through your property, and they follow and are confronted by your dog, whom then attacks, they have a right to defend themselves, and that includes the K9.
3. Well, they need not stop and ask every homeowner if they can run through their backyard while in pursuit of a fleeing suspect, that's just foolish to think that they should. As a homeowner myself, I know that if the cops are running through my yard after someone they have my implicit permission, and I hope they catch the suspect without injury to themselves. Further, if my dog attacks them coming through, and they have to protect themselves from him, then they have to do what they have to do...I understand...
I can only guess by your answers here that you want police at a disadvantage.