Ok, the driver was reluctant to move over when flashed, but what did you think was going to happen when you punnish him/her by blocking his overtake of the next car, grow up.
Now I've seen the vid, tbh wtf were you doing blocking him? He got out of the way, you should have blasted past with a wave like the previous rather than sit at his side and block him in
Happens to me all the time, move out of the way from some tosser ( not saying you are ) who then slows down and means I have to knock cruise off and brake. Doing 45k miles plus a year, this is in my top 3 of annoyances....