So I recently did a bit of a deeper dive. The (hivemind) deployers tell unit control that they can be selected to give the spawned biters a path to follow. but that same data is used to make the list for all the entities that can spawn units. And I have a choice now; allow biters to be spawned via unit control and give the biters a base path to follow, or do not allow unit control to spawn biters and let them all clutter up at the spawn exists.