If the truck was causing the problem, then the truck (at some safe point) should have pulled over to let traffic pass. He was being inconsiderate to fellow drivers.
The van was also being a jerk about things. While I can understand his frustrations, what gives him more right to cut others off.
I can see trying to pass 1 or even 2 cars when possible. Trying to cut off 5+ cars at a time is foolish and possibly dangerous in my opinion.