I agree it was self defense. With the knife out and the guy saying, "I'm going to kill you!" it is more than reasonable to consider your life on danger. But, at the same time the response he recieved from his provocation is so predictable you would only be a little nuts to think he had to foresee this outcome. To be clear, I think that is very unlikely; it makes way more sense the guy is just a huge idiot.
But, if he had foresight he would say, what is the likely outcome of arming myself in my the middle of a tense crowd that has seen violence and is on edge, starting a scene, and assaulting a woman? Considering how the energy has been on the streets, considering the number of people around, it is basically a numbers game. The bigger the crowd, the more likely the odds some witnesses will go after the assailant. I am not even sure how many witnesses there were, but if it was a lot, I would think you could 100% predict someone would counter attack. Predicting the knife would be less likely, but serious injury would still be reasonably expected oddwise. So, it would have been quite reasonable for him to assume that he was putting yourself into a situation where his gun would be required to safely exit the encounter.
Now, I'm assuming a fair amount, because for events before the above video I am just going off the above comments. If the scene where the guy assaulted the woman wasn't how I imagined it above, let me know and I'll delete this. But, from the descriptions I read, I can't help but wonder what his expectations were, or was he just in a blind rage with no thoughts?