Reminds me of an incident that happened to my coworker. He was driving this huge full size van and needed to make a right lane change since his lane was ending. Car next to him had plenty of time to either go faster or slow down and let him in but didn't and just paced next to him. So he charged into the lane and forced the guy off the road onto the shoulder.

Anyway, I hate people who weave their car in and out of traffic without warning and sufficient following distance. So I understand how the guy felt. He did something I wish I have the guts to do. But yeah he's in the wrong and should pay for all teh damages.