How is it hard for you to imagine, and how do you find it unreasonable, that the Cowboys wouldn't want to continue with a 7th round rookie who clearly isn't ready for the big stage?
I don't "find it unreasonable". The decision to make a change now is understandable, and is not the subject of my criticism.
You act like DiNucci earned the starting position and the Cowboys are snatching it away after one game, but the reality is he was just the guy left standing after injuries to 2 other players, and the team never actually expected or wanted him to play this season.
I agree that the team probably never expected him to play this season. Yet, he was on the active roster, and deemed capable of playing. Often, teams have to resort to their 3rd string QB. The Cowboys have been lucky in recent years taking the very risky approach of keeping only 2 QB's. A player on the active roster should be capable of, well... actually PLAYING. I don't blame DiNucci, I blame a coaching staff that has mis-evaluated, and a GM that has underinvested.
Green Bay fields one of the league's best QB's (a first rounder), yet they used their recent first round pick on another QB. The Cowboys GM on the other hand, has invested a total of one late fourth round pick, and a seventh round pick, in the most important position on the team. Pretty clear which approach is more successful.