You will notice that the Jackets player punches Xhekaj in the head while he is already on the floor. This is a very bad move, because even if strongmen hit each other, there is still a code of honor to respect.
Mathieu Olivier tried to explain his gesture, but let's say it's quite hard to believe, especially because the blow clearly went off when Xhekaj was on the ground. We'll give him the benefit of the doubt...