One of his campaign talking points was that he was going to change the way we waged our war on IS, because the Obama administration always told everybody what he was going to do before he did it, and how stupid was that?*
Perhaps they thought that would avoid the very thing that happened: Russia suspended the coordination agreement that was in place to prevent unintentional Russia/US combat casualties.
Also, we shouldn't forget that in addition to the actual
...but hey, do what you want...you will anyway.
*UPDATE 10/10 - not just during the campaign...