Bronco "apologists" v. Bronco "haters."
It would seem to me that those who are most frustrated with Bronco (myself included) are those who first bled blue during the 80s, when we dominated our rivals and were frequently players on the national scene both with individual player awards and team rankings.
OTOH, it would make sense to me that those who most adamantly defend Bronco are relatively recent fans (2000s, for example); fans who don't really know any differently other than the notorious Crowton years and are therefore afraid to make such a significant change.
Obviously, there will be exceptions, but I wouldn't be surprised if my theory generally holds.