You claim in many of your previous posts that there is absolutely no way that Tanner could be better, but the only reasons you have given as to why is that the rest of the team (o-line, receivers) are bad and none of this is Taysom's fault. But you haven't seen Tanner play with this team at all, so there's no way you could know if that's really the case.
As for the coaches, they are human. They make mistakes, and they often make emotional decisions to the detriment of the team. Bronco did with his QBs, particularly in playing Riley while hurt further injuring him because Riley was a "great leader" even if he was a horrible QB.
The original poster seems to have an in and has seen in multiple practices that Tanner is the better passer. Unless you can refute that with the same types of observations, then your argument does not seem valid.