When you said previously 'contributing factors', I thought you meant that the choking was not the sole cause of death and there were factors like his drug use that played a role in having him die more quickly from the choking than he otherwise would have. Which, from articles like the one linked, is precisely what the defense team argued. And obviously Penny couldn't be expected to know the guy's medical history or the details of his drug use, but he certainly knew that the longer he kept choking him, the higher the risk became.

Quoting from the article linked (I believe USA Today is generally considered fairly middle ground as far as any political bias goes, right?):

"The defense team also argued Penny's chokehold alone could not have caused Neely's death, and that Neely suffered an extreme sickle cell crisis on the train floor, blocking the flow of oxygen. However, a medical examiner testified Neely's death was caused by "compression of the neck," and not other health issues."

If you're telling me that the choking was not at all a cause of death, then it seems that once again in the culture wars, people have not only different opinions but are reading entirely different sets of facts in their news sources...