Ben, glad you are fine. You can fix anything except death as my 82 year old father says; certainly a mirror.
When one chases an idiot, what does one expect to find? Glad you didn't.
I can clearly hear your turn signal and you had left more than ample room for the second rider. He hit you on purpose, and that you can see given the room he had, and how he maneuvered towards and then away from you.
You can see how his handlebar is in your lane,
has his right hand is off his handle so he can hit you without injuring himself.
Finally swerves away.
