I don't think it's ridiculous, but most of the facts fit my 'fantasy'.
Sure "management" may have said keep the speed up, that's entirely possible. But "management" didn't instruct them to perform "HARD BRAKING" (all caps).
You might be correct about that one part.
There was no braking by the engineers. There was an automatic brake, but that was obviously inadequate.
What caused the 'automatic brake' to engage ?
They don't say: https://www.deseretnews.com/article/900005974/train-speeding-50-mph-over-limit-before-deadly-derailment.html but my guess is that it went off as the train derailed, not before. The article says that the sensors and controls for automatic braking were installed but not turned on. I suppose it is possible someone thought they were already turned on.