I can't be certain, but I
suspect it was one of those quick fixes in the development cycle, where the
guys just implemented a straightforward fix instead of looking closely at the deeper issue. (Something that still happens from time to time in the SCP.) It's caused by the different ways support ships dock.
Support ships have a unique "has-docked" mode, called
AIS_DOCK_4. Everybody else uses
AIS_DOCK_4A. (Yes, that seems backwards.) The difference is that
AIS_DOCK_4A lasts for only one frame before the AI exits that mode. In contrast,
AIS_DOCK_4 lasts for as long as a ship is repaired.
The mission log is only written in
AIS_DOCK_4A. There are two possibilities: either
forgot to replicate the mission log in
AIS_DOCK_4, or they did implement it but then took it out. This is because, since
AIS_DOCK_4 is processed every frame, you'd get the mission log written every frame and pretty soon your mission log would fill up with dock entries.
To fix this, you would have to add the log in such a way that it's only called once. This could probably be accomplished by putting it in the same if() statement as the
REPAIR_INFO_BEGIN call.
(This is all guesstimating, by the way. I peeked at the code, but didn't run any tests.)
In actual answer to your question, no, I can't see or think of any reason why support ship docking shouldn't be logged.