The problem is that when using them for defence, you don't want them to auto-move to auto-acquired targets, or alternatively, no auto-FRD (no these are not the same, look at the blade spawner's behaviour)
However, when using them for offence, you will want them to auto-move (given they are in a move/idle state that allows auto-moving to targets). How is the game supposed to know which case you want?
I think that highly voted up feature request "suppress auto-FRD command" would really help out with different needs for defence and offence such as these.
EDIT: Clarification, when using them for defence to boost immobile stuff, like turrets. When using them for defence to boost mobile stuff, like fleet ships, you want them to move.