facepalm
Right, I understand you now. You are being pedantic about the definition of Kessler Syndrome, assuming people are using it to refer to a permanent status. Gotcha.
In short, you don’t disagree, you just aren’t using the same words to mean the same thing as everyone else, leading to confusion and conflict.
Kessler Syndrome, even if it “only” lasts a few years, would be devastating. That is what people are worried about, and that is what could happen, even with low earth orbits. Given big enough pieces of debris, the “any significant period of time” you refer to could certainly be significant enough to cause lasting problems.
“That was left-handed!”