In all fairness, yesterday, Khabib and about 10 of his Jihadi gang surrounded Artem Lobov, McGregor's teammate and confronted/assaulted Lobov.
(See: Video: Khabib Nurmagomedov and Artem Lobov in altercation in Brooklyn hotel)
So, McGregor gathered some of his teammates for some payback.
Wrong? Certainly. But hardly unprovoked.