I suspect that Dana White encouraged McGregor to show up in Brooklyn - he adds a lot of hype to the event. I doubt White was behind the specifics of the attack on the bus but he was undoubtedly stirring the pot and this is what ensued, and now White is being a bit of a drama queen about it. There is a lot of WWE about his whole schtick.
Khabib probably had more to do with it when he and 10 or so of his jihadis surrounded and confronted McGregor's teammate, Artem Lobov earlier today.