Lets just say for the sake of arguing, I defend myself from an attacker with pepper spray successfully. And then the police refuse to take this criminal to the police station under arrest unless I take him there, or to a hospital for treatment where he will be observed by LEO.

I am willing to bet that between the scene of where I defended myself and where the police have forced me to take someone to affect a citizen arrest....I'm bound to drive fast over a few potholes. I might find that his head hit my windshield hard enough, several times to break the glass, its a horrible thought but I can get my windshield replaced for free through my insurance. It is possible that the spray affect this attacker so strongly that he stopped breathing. It's possible, the officers were gagging just being near him. So I had to do CPR on him and in the process a few ribs were cracked. That's pretty common in CPR. I mean I wouldn't want the guy to die on me while I was affecting a citizens arrest on the way to the police station, right?

Of course, I would personally never think to do anything like that. That would be unheard of. How uncivilized.