I understand.
It means you face reality rather than be afraid to convince yourself against logical thinking that you should try a better option out of fear it's not going to work, either. "Overreacted?" As has been said, every game counts. Thornton has had absolutely NOTHING so far, which has earned him 3 straight blown saves IIRC. Give him one more go and if it looks the same, there is no way to defend leaving him in the closer role. If you think this is an overreaction you're lying to yourself.