I think it's fear. How do you measure that a manager is doing a good job?
If you only judge by the team shipping on time or hitting their number, then a dictator/slave driver looks pretty good early on.
If you judge by employee morale, someone that misses numbers but doesn't overstress their team can look good.
Unfortunately, things like employee churn are lagging indicators, so if a manager wants to look good, the temptation will always be there to take credit for themselves out of self-preservation, even if it's all in their head that they're in any danger of losing their job.
If you only judge by the team shipping on time or hitting their number, then a dictator/slave driver looks pretty good early on.
If you judge by employee morale, someone that misses numbers but doesn't overstress their team can look good.
Unfortunately, things like employee churn are lagging indicators, so if a manager wants to look good, the temptation will always be there to take credit for themselves out of self-preservation, even if it's all in their head that they're in any danger of losing their job.