So what, the first responders killed him and it's their fault? I don't know where you're going with this line of argument, but for someone to be held responsible for a death (whether as murder, manslaughter, criminal negligence,...), it's certainly not required for them to be present at the moment of actual death. There's plenty of things that cause death more slowly, but that medical professionals may still not be able to avert during that time.
And in your example, supposing each of the four attacks mentioned was done by somebody else, it seems perfectly possible that each of the four by itself was sufficient to kill the victim even if they didn't do so instantly, in which case all four attackers could be found guilty of murder, not only the one who struck last or the one that worked the most quickly.
Clearly there was debate about the extent to which other factors outside of Penny's control contributed to Neely's death. But you seem to be taking a more radical position than even the defense in the trial, you're acting as if the choking was almost irrelevant? As I mentioned it might be that you're reading other articles with entirely different facts, or different statements from medical examiners, than those in mine, in which case I'd like to see those as well.