But the rider he punched Preben van Hacke (Sport Vlaanderen - Baloise) thought a DQ was too harsh.
"Sometimes this happens in a race. He did not hit my face, but in the hip," Van Hecke told Norway's TV 2.
Straight after the race, Boom (LottoNL-Jumbo) felt his move was justified.
"He was on my wheel and I almost crashed, I almost f*king hit the ground. Sorry for the language. But I would not crash, especially when an idiot does something like that," Boom said to TV 2.
But he later backed up the rage truck a bit and apologised via a statement on the LottoNL-Jumbo Twitter account.
Norway's Edvald Boasson Hagen (Dimension Data) won the stage.