I think those statements occur too frequently, but I also think they are true about 20% of the time. I think the statements are intended to distract from the players performance and put all the heat on Gary. It's better for the fans and media to spend time focusing on Gary not being able to change his signals than talking about how badly a certain LB/DE/CB/WR/RB/QB played.
You have come up with a reasonable explanation that has been confounding us. This must be what's really happening, otherwise, it gets too scary to imagine.