I don't think they hit him on purpose . They probably didn't think the rear dually fender flare was going to clip the other vehicle . Plus the other vehicle started moving forward as the truck tried to get in front of him.
When he says dumbass it reminded me of Beavis and butt head
But also the lanes to the left of the BMW were turn lanes... I could see if there was something that happened prior, but the truck was in the wrong anyways for using the turn lanes as he did.
I mean maybe the BMW was being a douche and not letting the truck in.
Like the truck was originally trying to get into the regular lanes and the BMW was goading him after the fact by leaving space in front of him.