The CHOKe packet scheduler

Take a long pipe with a several ms of delay. Run a single TCP flow across it. Observe that your flow gets nowhere near line rate, but instead it sawtooths against line rate and leaves the link idle for a significant amount of time.

Yes, a single flow is a corner case— but not not an outrageous one. The behavior also holds true for a small number of flows, especially if they experience identical end to end delays.

So there is the excuse you were missing.