So the graph you linked is nice, but it just tells us the obvious: you need to beat the hell out of a beer to get it to start noticably staling, i.e. “Stage C”.
I guess I just don't understand what you are saying. If it isn't noticeable, then who cares?
What i'm saying is this: Bamforth is talking about stereotype oxidation flavors: cardboard, skunk, etc. What we are typical talking about is subtle flavor loss experienced by everyone, even us, i.e. loss of hop aroma and flavor, malt profile changes, etc.
The breakdown here is when people think we are telling them that they are making wet cardboard, skunked vinegar beer, which we are most certainly not. Everyone here, especially those viewing and responding to our posts is savvy enough to know that there is more nuance and subtlety involved.
I like discussion and don't want people on the defensive. That doesn't help anyone. With that said, everyone, including us, needs to be honest about faults and interested in fixing them and improving. Or maybe they don't. Far be it for from me to tell anyone how they should brew or what they should be interested in. YMMV, but more information is always better than less (IMO).