Yeah, I don't think this is the bikers fault. The biker was an idiot for kicking the sedan but it looks to me like the accident occurred as a result of the sedan driver's retaliation to the biker. It looks like the sedan driver tried to take out the biker.

If you flip someone off and then they shoot you, is it your fault because you flipped them off? Not quite an eye-for-an-eye in either case.