Whoah, whoah. I certainly didn't say the man deserved to die. Or be injured at all. And, of course, I'm just speculating. But it does seem to be a problem with our society that men will rush to the aid of a woman in distress whether or not she actually needs it. For all we know (and again, just speculating), she could have been the one who turned the argument "physical" in the first place. And based on the actions of the woman afterwards, it didn't appear that she deserved to have this man die for her. I do believe the unfortunate man was attempting to do the right thing. I never suggested otherwise.

Let me illustrate a hypothetical example. Let's say the man and the woman were walking down the street having an argument. They're both really pissed off, and then the woman just starts wailing on the man. Beating the shit out of him. The man manages to forceably restrain her, but she's writhing and screaming for him to let go of her. Guy turns the corner and sees this scene and runs to the aid of this "damsel in distress." Now the man is being attacked by both his girlfriend and a random homeless guy. Things turn for the worse...

Now, if witnesses are correct (and why the hell didn't these witnesses call an ambulence?!) and the homeless man had been walking behind them for a while, hopefully he would have had better context than that, but you never know for sure.