Very quick opinion (would need more time to analyse) from watching the video:
- you were a bit of a douche for not letting this clown in to begin with, but he did barge in the end
- obvious brake check and the dumnuts then pulled over right after to show no one in front of him.
Thats likely going to be a refutable claim on the offendors part as this has been demonstrated here on /b before with the BMW on Beddington Tr. incident a few years ago where the brake checker had their insurance claim tossed - base on the dashcam footage.
Thank fucking christ you had a cam.
EDIT - anyone saying 100% rear-ender fault always - please check the thread in question:
https://forums.beyond.ca/threads/369...dington%2C+bmw
Accord driver's claim (the brake checker) has been 100% denied for damages (not even his vehicle by the way) by the girlfriend's (victim) insurance company.