The MARADMIN applies to all Marines under that command, and the civilians are "accessories" to the unit, therefore they are listed separately.
In regards to the rationalization that it is "just a NUC for MCRC," this stuff matters when the promotions board convenes and they see your file and promotion photo.
In regards to the "tip of the spear" comment, Marine Corps Drill Instructors are a part of MCRC. Are they not the tip of the spear? Is it safe to say that without recruiters, we would not have fine Marines winning battles on the field and maintaining the very aircraft we fly or wish to one day fly?
That's all for now with my pontification.