Originally Posted by ElVee

Not to be pedantic, but change "plausible" to "reasonable" up above, and you have some valid legal arguments.

a- For the first part, it probably is reasonable that RR guy was feeling imminent threat to himself and his family; in fact, life-and-death threat.

b- For the second part, we're dealing with mob violence or even a riot (it's a legal thing, not talking a race riot here), i.e. a group of persons coming together with shared intent. In this case, if that biker is part of the biker group, he'll probably be considered part of the riot group and responsible for violence caused by such group, even if he's suddenly not "feeling" like being a part of it anymore. It is probably reasonable to say RR guy would not have distinguished that guy as *not* part of the group.

To turn that around to be less awkward, RR guy probably reasonably believed that biker a part of the riot group and not an innocent bystander.

The law almost certainly will consider that guy part of the riot group.

A lot of this is thanks to the biker's own video.