We know the matador knew the risks, so does a mountain climber, sky diver, or racing driver.
You're comparing apples with oranges with this argument. Firstly,a mountain climber, sky diver or racing driver puts only himself at risk; he has a support team to assist him achieve his goal but ultimately, he's solely responsible for his safety.
Secondly, the support team members have the capacity to refuse to be a part of that extreme sport; they have the ability to walk away, at any stage, if they feel that anyone's safety is being compromised or that someone stands an above average chance of being hurt or injured.
The bull has none of these options. It doesn't have capacity to agree or disagree to be baited to a rage and then stabbed. I'm as sure as I can be that, if it did have that capacity, it would tell you to sod off. The bull has been conscripted; whether willing or not and therefore reacts in the only way it knows: to kill. The matador knows all of this (because he's the intelligent one) and decides to take the risk anyway. On this occasion, it's matador 0. Bull 1.