Surprise, surprise law boy, if you rear end some body; IT IS YOUR FAULT PERIOD.
Learned that the hard way.
Your declaration is GENERALLY true. However, it is not always true. In this case it is true that Jenner rear ended the car in front of him. There are two howevers in this mix:
However, Jenner was not speeding and the original accident was caused by others and created a stop short incident. Jenner is responsible for his vehicle being able to stop in time - true. As such, he is at fault for the second collision.
However, the cause of the death was a subsequent accident caused by another vehicle. This is the third collision which Jenner is very likely not to be responsible for depending on the circumstances and what the prosecution can prove.
The general rule in law is that the fault lies with the last person that could have avoided the accident. Jenner’s lawyer will likely argue that Jenner did not start the chain of accidents and was not the cause of the last accident and as such, is more a victim than villain. This will make the prosecution’s efforts much more difficult.
Standard disclaimers apply - I am not a lawyer, I do not have all the details, this is just my opinion and is based on news reports, etc.