Except that it is a GMs job to sort out problems. So I have no sympathy on the busywork front.
In your example you were able to sort out what you did. That is great. For many that won't be true. Perhaps they just do not see the behavior as offensive or maybe they just don't interpret a rule the same way as SE intended it. For the latter see the huge threads when the new examples of actionable behavior were put out not long ago. Individual interpretations of those example were widely varied to the point where some people had diametrically opposing views on what they meant.
If the GM is doing their job properly and looking in to the problem incident to make a fair judgement it would not add "busywork" to allow them to give a statement of what the infraction was without identifying a specific incident or person. Simply saying "griefing" is far too general.
EDIT: I actually rather suspect this is a policy dictated by SE's legal team to cover themselves vs laws varying in multiple countries. In which case it is unlikely to change.