"Lt Northrop, we are not a vessel built for war, nor are we equipped as one.  As the Captain has stated, we could equip these systems easily, we have the power, yet, we need the power we have to be able to analyze space around us and find the shortcuts between points A and B.  The capabilities you recommended are offensive and speak of tactical superiority, neither of which we need with our shielding abilities.  These alone will protect us from the species that you have mentioned."