Your logic is nonsensical. If a person is beaten to death, that the person died of "internal bleeding" would not then be a defense claiming it wasn't the impacts that caused the death - but that is your logic. It also is your logic that the defense could argue that if the person beaten to death had been in better health the person wouldn't had died.
All that is ridiculous logic. IF the assault brought on the heart attack, the assault is what caused the death.
"Your honor, it wasn't raping the 91 year old that killed her. She did not die from being violently assaulted. She died of internal bleeding. She had been a fully healthy young woman she would not have died. Therefore, there was no murder." This is YOUR absurd find-anything logic.
If someone dies of a heart attack while being illegally violently assaulted it is murder or manslaughter. You say otherwise.
The question in this instance was whether the assault was criminally illegal. Was it legal for that officer to jump on his back putting him into a chock hold? THAT is the legal question.