Are we getting too focused on the minutiae of take off procedure when we still have no clue as to what actually happened?
I have seen no reason to distrust the crew, plus the reports that they had requested to not use this aircraft again would surely indicate that they would be on full alert when forced to fly it again.
Consequently I believe that a catastrophic mechanical failure is at least as plausible cause a cause as crew failure.
My only issue is the total absence of any reported communications. Even at 500', if things go bad, there is time to say something.