There are many sides to any given story, but if this open letter by iD is true to at all, it is understandable why they wouldn't want to continue working with Mick Gordon.
But. There's one so ironic thing here that it must not be overlooked. We, as gamers or denizens of the Internet, usually root for the underdog. At the very least, usually large corporations like Bethesda (very much to a lesser extend iD) are on the receiving end for our dismay. And yet, if iD are the good guys here... we are effectively rooting for Chad.