A precedent embalms a principle.

Once something has been done a particular way, the reason behind it stops being examined and the practice hardens into a rule. The original thinking is preserved and also made unavailable, since nobody now needs to understand it in order to follow it. That is convenient until circumstances change and the rule outlives what it was for. Most institutional absurdity began as a sensible decision nobody revisited.

When you meet a policy that makes no sense, ask what problem it was solving when it was made. Then ask whether that problem still exists, and be willing to find that it does.